The human brain is also only one of the systems involved in human actions and decision making. I’m not talking about any kind of spiritual stuff. I mean actual systems that influence brain chemistry.

There are areas of cognition in which is quite possible that important decisions are being made outside the brain, and our executive function rationalizes the decision like Mayor Quincy running to the front of a protest to “lead” it.

I think one great layperson introduction to this kind of systems interaction is contained in the book Gut (Giulia Enders).

I don’t know if we literally need to simulate each subsystem, but it does lead me to believe is that we don’t yet understand the system that we are trying to model. It isn’t just neurons, and “just neurons” is hard enough.

That said, there’s a lot to be achieved by throwing more more power at the problem. Many problems in the realm of imitating humans, from playing chess to visual recognition systems, were not defeated by specialized approaches but eventually fell to sheer processing power. For me this means X is probably 5+ generations, and a lot of that is simply because I can’t picture what the future looks like further down the road than that