I never understood why we believe humans don't backprop. Isn't it that during the day we fill up our context (short term memory) and sleep is actually where we use that to backprop? Heck, everyone knows what "sleep on it" means.

Brains are not doing linear algebra, and they don't follow a concise algorithm.

What LLM do is even farther away from what neural nets do, and even there - artificial neurons are inspired by but not reimplementing biological neurons.

You can understand human thought in terms of LLMs, but that is just a simile, like understanding physical reality in terms of computers or clockworks.