> But then, people have simulated that at high scales
People have thrown vast amounts of neurons in a bag, and have tried organizing networks in highly regular ways, but we have yet to apply what we know about brain tissue organization. We've done the equivalent of throwing a bunch of wood and concrete into a pile, so it should be no surprise that it doesn't look like a home. IMO it's quite remarkable that this approach has taken us so far!
That's fun to read, but not sure what you mean by brain tissue organization.
So there is still a missing process that turns organisms into self-sufficient survival bots that also gives brains some level of consciousness as a consequence and it isn't trivial to recreate. Otherwise we would be crawling in artificial minds with their self-induced purposes by now.