Are those important questions that need to be answered? Rather, you should be asking whether you could use backprop and NNs to create something other than text predictors. What have LLMs changed about your conception of intelligence?

As far as I can see, none of the hard problems of intelligence that we had a decade ago got touched. What LLMs ultimately changed is the way I see language. I've underestimated its power, and I will admit, the companies making these models went far further than I could have imagined with them.

But intelligence and AI have a high hurdle to clear, and it won't be done with LLMs.

Revealing the secrets of intelligence will involve new concepts and understanding that that we don't have now. LLMs will be helpful with the plumbing and as replacement for natural evolution, but not so much natural intelligence.