There is a reason for this: it makes us able to adapt to _any_ environment on earth. We learn everything from our parents/guardians who have learnt all the 'right' ways of doing things. Look around, are we not the dominant species?

From our point of view we're the most dominate, but from other points of view you could easily argue that bacteria are the most dominate. There are a lot more of them and they will almost certainly outlive us.

This doesn't really seem relevant when we're talking about the development of knowledge through training in humans.

Instinct isn't "training", really. Don't conflate neural networks and genetic algorithms in people or AI... :)