What influenced the development of the King's Indian Defense? The King's Indian Defense is characterized by the moves 1. d4 Nf6 2.c4 g6. (As opposed to 2. . .e6, with the intention of developing the Bishop to the Queen-side.) Black aims for a strong King-side offense with sharp tactical play. The Classical line:

[FEN ""]
1. d4 Nf6 2. c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5


Nimzowitsch and others of the hypermodern school popularized the Nimzo-Indian and Queen's Indian defenses eary in the 20th Century. The King's Indian was known, but was seen far less frequently until David Bronstein started playing it in the 1940s and 50s.

So, to the question, what factors brought the King's Indian to prominence aside from Bronstein? What developments in theory advanced its use compared to the other Indian defenses?

(To clarify: I'm coming at this as someone who's unrated and no more than a casual player at best. I'm looking more here for the historical aspects and understanding of the times, though I won't turn down discussion of modern theory.

Additionally, I'm aware that this is subjective. I'm fairly confident it fits into "good-subjective", given the nature of Chess.SE. There hasn't been any major discussion on the KID here, and I'd like to see what the minds here have to say about it, given how important it is in modern play.)
In all the Indian Defenses, in general, Black allows White to occupy the centre with his pawns.

Nonetheless, in Nimzo-Indian and Queen's Indian Defense Black has many moves to attack White's pawn centre very early in the game, thus White cannot gain too much space.

King's Indian Defense (and Gruenfeld Defense), on the other side, really do not care that much for the first 4-5 moves of White, so that he can occupy the centre with an "horde" of pawns (see for example the Classical Variation, the Saemisch Variation or the Four Pawns Attack), with a huge advantage of space.

Since hypermodern principles in chess were born only in early 20th century, they were not universally accepted before '40s. And having such a big space disadvantage in the opening was seen with suspect (if not explicitly considered "strategically losing"). That's why, in my opinion, KID had to wait to be considered consistent enough to be played regularly by top players.