Do you have much experience with brains? Are you aware of the ratio of computational capacity to energy requirements that is as yet unmatched in power?

Not to mention that, as a system, the brain is highly efficient in reusing modular structures for increasingly complex tasks.

I have a feeling when people mention "AI modelled after a brain" they consider a simplification of neuronal dynamics to be how to achieve that. But that is a very naïve way to do it. Looking at it from the system level is the more fruitful approach, IMHO.