Why did God banish Adam and Eve for eating fruit? Yes, He told them not to but if you can humour me a little, why should this punishment be regarded as fitting the crime? It’s just fruit, right? Isn’t God testing our patience with such an injunction? Would you respect me if I told you not to touch my really delicious pot of lamb stew because you will be dead if you do, especially if the children are having a really tasty dinner?
You've missed exactly what Adam and Eve missed - the tree of Life. There it was in the midst of the garden. 

And there it was - the Word of Life - 'the tree of the knowledge of good and evil, thou dost not eat of it.' 

It isn't food. You can't digest it. Partake of it and you will die.

But another (created) spirit drew near. (For they had not taken of the Tree of Life in the midst of the garden. They had not partaken of the Word of Life which said 'the tree of the knowledge of good and evil, thou dost not eat of it'.)

And Eve hearkened and ate. And Eve gave to Adam to eat. 

And in that very day, they died.

This is about human nature. It is a matter of how humanity is to Live. Adam was made a living soul and he lived and breathed. But there was a Tree of Life in the midst which he needed. And he did not partake of it.

He chose to seek sustenance from another direction. From knowledge. Rather than partake of Life, he chose knowledge. Which assumes his own ability to see aright and to do aright what he sees. 

Rather than to partake of Life itself.

He wishes to be independent of the Deity (in whom is Life) who made him.

Chooses to hearken to a created spirit, encouraged by a created woman. 

And he dies.

And he is banished from the garden, for he has failed in his humanity to rise to the purpose of the Creator who made humanity for a purpose.

This is profoundly and fundamentally spiritual.

It's not about physical fruit.