What's the goalpost here though? modern "AI" stuff we previously thought not possible, Proper full human-brain simulation; or General form of higher AI that could come from either place?
> The amount of parallelism in the human brain is enormous.
That only demonstrates the possibilities yet to be explored. biology has millions-of-years head start; what's possible today could be balked out a few centuries ago by the same argument as yours. You say "We are just now getting multimodal LLMs" like it's somehow late.
At a fundemental level, what holds back biology is all the other things it does (ala staying alive) and the limits imposed (e.g. heat etc) that a purpose-made device can optimise on. Any physical, thermodynamical of communication-theoric argument over what's possible would hold back both biological and mechanical devices. Only there are fewer material constraints for machines - they can even explicity exploit quantum mechanics.
> Sorry, but the notion that we are close to AGI
Seems we are arguing different things. I went back through the thread, and believe the proposition is: "us, humanity, being able to build AI or something being very close to that", which I translate as a comment on our literal species. I took your statement "From the energy efficiency perspective human brain is very, very effective computational machine" as being in that scope, and not just a reference to the current era (or Decade!).