But that has never been proven that this is how indeed human acquire language; it is essentially a hypothesis. We may as well do it the way LLMs do - some undifferentiated networks acquires the grammar by unknown means.
> We may as well do it the way LLMs do
We almost certainly don't learn the way LLMs do, it's just too data inefficient.
And I don't see what current LLMs can say about a universal grammar in the Human brain, unless there is proof that a LLM-style attention mechanism exists in the brain, and that it is somehow related to language understanding.
LLMs on the other hand can easily learn these non-human grammatical structures which means that they are not the way humans do it.