Reasons for Restriction of Tridentine Rite post Vatican II If I understand correctly, the Second Vatican Council ordered the revision of the liturgical books based on the constitution Sacrosanctum Concilium. These revisions where carried out in the years after the council and implemented in 1969/70.

Even during the council and even more up to the implementation of the revised books there was plenty of criticism of the council as a whole, specific teachings in particular and of the liturgy and the upcoming liturgical reform.

If my research is correct, in 1974 the congregation for divine worship announced that no more permissions would be given to those who intended to celebrate the liturgy according to the pre-vatican formulae.

This situation eventually led to the founding of SSPX and the schismatic consecration of four bishops by Marcel Lefebvre.

Later on the restrictions on the use of the older liturgy where loosened until Benecit XVI made access to the now called extraordinary form widely an mostly unrestrictedly availably.

This leads me to the following two questions:


What reasons where there to heavily restrict access to the old liturgy after the council?
Was it expected that these restrictions might give further rise to the SSPX-schism (or similar problems within the church)?
Reasons for Restriction of Tridentine Rite post Vatican II

There will never be published any official reasons for the seemed restrictions of the Tridentine Mass and it's liturgy. If one can find some then they are free to make a response to this very question.

The real reasons for the restriction of the Tridentine Mass promulgated by Pope St. Pius V seem to be more of a conundrum than anything else.

Before getting involved in this answer, I wish to state that I attend both Forms of the Sacred Mass in use within the Roman Rite (the Extraordinary Form of the Mass (EF) and the Ordinary Form of the Mass (OF)). I do not like to  criticize either Mass within the Roman Rite. Both can be prayed in a holy manner and both are valid forms of Catholic worship. However as I tell many others, the Tridentine Mass in more conducive to my spirituality and thus is the one I prefer to attend. If a traditional priest is continually blasting apart the New Mass from the pulpit, I will likewise go somewhere else. For myself the opposite is equally true.

I know of a certain French prelate that desired to say the Mass of Pope Pius V and went to Rome in 1978 to seek out permission. Rome reply  from the particular congregation was simple: "No, say the New Mass only." It is obvious that Rome truly wanted the New Mass in and the Tridentine Mass out.

Just a few points before really digging into this question.


As for your research (which you do not say what), you state that "in 1974 the congregation for divine worship announced that no more permissions would be given to those who intended to celebrate the liturgy according to the Pre-Vatican II formulae." That is not completely accurate. For example, in France the clergy were not obliged to say the New Mass until the French bishops had actually approved the French translation of the Mass. That happened in 1977. I remember a certain French abbot telling me that when this took place, he told his community to obey and hope for better times and hope that the former "Old Rite" may come back.
Priests of a certain age were never obliged to say the New Mass.
Pope Benedict XVI stated the Mass of Pope St. Pius V was never abrogated.
Rome actually published yet another Missal during the Second Vatican II Council, which almost everybody in unaware that really existed: The Interim Roman Missal of 1965?. I have actually seen this Missal, even though they are now extremely difficult to find. The Missal was in Latin and English and was basically the same Mass as in use in the Extraordinary Form of the Mass.


Now for the crux of the matter in question. The Second Ecumenical Council of the Vatican, commonly known as the Second Vatican Council or Vatican II, addressed relations between the Catholic Church and the modern world. The council, through the Holy See, was formally opened under the pontificate of Pope St. John XXIII on 11 October 1962 and was closed under Pope St. Paul VI on the Solemnity of the Immaculate Conception on 8 December 1965. As you state in your question "the Second Vatican Council ordered the revision of the liturgical books based on the constitution Sacrosanctum Concilium. These revisions where carried out in the years after the council and [were to be] implemented in 1969/70," as seen in Pope Paul's Apostolic Constitution Missale Romanum. "We order that the prescriptions of this Constitution go into effect November 30th of this year, the first Sunday of Advent."

What were the reasons for the restriction of Tridentine Rite following Vatican II?


Rome desired that the New Mass be made available to all the faithful and clergy alike. After all, Pope Paul's Constitution on the Missale Romanum clearly stated that "we order that the prescriptions of this Constitution go into effect November 30th of this year (1970), the first Sunday of Advent." Thus the Mass of Pope Pius V had to be put on the back burner. That much is obvious.
One of the most common reasons one will hear is that Rome desired more Scripture readings for the faithful. A fact that the New Mass tries to bears out. "Sacred scripture is of the greatest importance in the celebration of the liturgy. For it is from scripture that lessons are read and explained in the homily, and psalms are sung; the prayers, collects, and liturgical songs are scriptural in their inspiration and their force, and it is from the scriptures that actions and signs derive their meaning. Thus to achieve the restoration, progress, and adaptation of the sacred liturgy, it is essential to promote that warm and living love for scripture to which the venerable tradition of both eastern and western rites gives testimony." - General norms Pope Paul"s Apostolic Constitution goes on to state that "in prescribing that "the treasures of the Bible are to be opened up more lavishly, so that richer fare may be provided for the faithful at the table of God's Word" (ON NEW ROMAN MISSAL) It also goes on to state: "According to the prescription of the Second Vatican Council which prescribes that "a more representative portion of the Holy Scriptures will be read to the people over a set cycle of years," and of the readings for Sunday are divided into a cycle of three years. In addition, for Sunday and feasts, the readings of the Epistle and Gospel are preceded by a reading from the Old Testament or, during Paschaltide, from the Acts of the Apostles. In this way the dynamism of the mystery of salvation, shown by the text of divine revelation, is more clearly accentuated. These widely selected biblical readings, which give to the faithful on feast days the most important part of Sacred Scripture, is completed by access to the other parts of the Holy Books read on other days."
The Tradentine Rite had only one Eucharistic Prayer (The Roman Canon) whereas the New Mass has the Roman Canon, plus three additional Eucharistic Prayers that the celebrant was free to choose from.
It was also desired that the Laity have a greater participation in the Mass. Thus vernacular languages were introduced into the liturgy, something that the Old Rite seriously restricted. The Sacrosanctum Concilium document desired "to promote active participation, the people should be encouraged to take part by means of acclamations, responses, psalmody, antiphons, and songs, as well as by actions, gestures, and bodily attitudes. And at the proper times all should observe a reverent silence."
Rome desired more Eucharistic concelebrations under certain circumstances. These were not done in the ordinary usage of the Tridentine Mass.



  
  Concelebration, whereby the unity of the priesthood is appropriately manifested, has remained in use to this day in the Church both in the east and in the west. For this reason it has seemed good to the Council to extend permission for concelebration to the following cases:
  
  
  a) on the Thursday of the Lord's Supper, not only at the Mass of the Chrism, but also at the evening Mass.
  
  b) at Masses during councils, bishops' conferences, and synods;
  
  c) at the Mass for the blessing of an abbot.
  
  
  Also, with permission of the ordinary, to whom it belongs to decide whether concelebration is opportune:
  
  
  a) at conventual Mass, and at the principle Mass in churches when the needs of the faithful do not require that all priests available should celebrate individually;
  
  b) at Masses celebrated at any kind of priests' meetings, whether the priests be secular clergy or religious. - THE MOST SACRED MYSTERY OF THE EUCHARIST 


These are the main reasons why Rome seems to have restricted the use of the former Mass of Pope St. Pius V. There are certainly others, such a priest facing the people during Mass. But it is still permitted to say the Mass of Pope Paul VI ad orientem. 

What I truly find as a real conundrum is that the Missal of 1965 permitted  most of the changes we see, yet remained in essence the Mass of Pope Pius V! Some have actually called it the  “Mass of Vatican II.” A copy of this "Vatican II Missal" as approved for the use in the United States of America can be found here and here. Some religious communities are using this Mass in their liturgy with the approval of Rome.

In desiring a greater love of the Mass and the Sacred Liturgy, some point out the use of communion on the hand as an innovation of Vatican II. Nothing is further from the truth. Sacrosanctum Concilium does not even mention it at all. Nor does any of the successive documents speak of it, nor the New Roman Missal, but only Memoriale Domini, which establishes it in terms of an indult.


  The practice of receiving Holy Communion in the hand first began to spread in Catholic circles during the early 1960s, primarily in Holland. Shortly after Vatican II, due to the escalating abuses in certain non-English speaking countries (Holland, Belgium, France and Germany), Pope Paul VI took a survey of the world's bishops to ascertain their opinions on the subject. On May 28, 1969 the Congregation for Divine Worship issued Memoriale Domini, which concluded: "From the responses received, it is thus clear that by far the greater number of bishops feel that the present discipline [i.e., Holy Communion on the tongue] should not be changed at all, indeed that if it were changed, this would be offensive to the sensibility and spiritual appreciation of these bishops and of most of the faithful." After he had considered the observation and the counsel of the bishops, the Supreme Pontiff judged that the long-received manner of ministering Holy Communion to the faithful should not be changed. The Apostolic See then strongly urged bishops, priests and the laity to zealously observe this law out of concern for the common good of the Church.
  Despite the vote, in 1969 Pope Paul VI decided to strike a compromise with his disobedient bishops on the continent. Given “the gravity of the matter,” the pope would not authorize Communion in the hand. He was, however, open to bestowing an indult – an exception to the law – under certain conditions: first, an indult could not be given to a country in which Communion in the hand was not an already established practice; second, the bishops in countries where it was established must approve of the practice “by a secret vote and with a two-thirds majority.” Beyond this, the Holy See set down seven regulations concerning communion in the hand; failure to maintain these regulations could result in the loss of the indult. The first three regulations concerned: 1) respecting the laity who continue the traditional practice (of receiving kneeling and on the tongue), 2) maintaining the laity’s proper respect of the Eucharist, and 3) strengthening the laity’s faith in the real presence. - Truth About Communion in the Hand While Standing 


No matter what Ecumenical Council the Church holds, there are those who will be at odds with it's decisions, no matter how trivial they may seem. Archbishop Lefebvre was actually was in favor of the Missal of 1965, but not the New Mass of Pope Paul VI from the very start. What went wrong is anyone's guess? Rome wanted the New Mass in and the Tridentine Mass suppressed. It's not clear exactly why. Some traditional groups, Deo Gratias, just would not give up the Traditional Mass and this forced Rome to start reopening up in favor of the Tridentine Mass. If it was not for them the Old Mass would have the way of the dodo bird.

For example, after Vatican I, Fr. Charles Jean Marie Loyson (10 March 1827 – 9 February 1912), better known by his religious name Père Hyacinthe, was excommunicated for refusing to acknowledge the infallibility of the pope. He was so sure of this that he left the priesthood and eventually got married.

Yet a more bizarre one from Vatican I is the case of Bishop Edward Mary Fitzgerald of Little Rock, Arkansas is as follows: 


  Summoned to Rome for the First Vatican Council in December 1869, he was one of two bishops to vote against the dogma of papal infallibility — an act that earned an entry in Universal Church history as “Big Rock versus the Little Rock.” Bishop Fitzgerald explained later that he voted as he did because he believed affirming infallibility would hinder his efforts to convert non-Catholics back in Arkansas. - Bishop Edward M. Fitzgerald


Unlike Fr. Hyacinthe, the Bishop of Little Rock was not excommunicated. In fact, he accepted the final outcome of the Vatican Council I. True to his own deep faith, Bishop Fitzgerald acknowledged his own faith in the theological truth of papal infallibility and was asked by the pope to be at the side of His Holiness when he officially proclaimed that papal infallibility(Pastor aeternus) as a dogma of the Catholic Church. He did.