Comment by kapsi

I asked ChatGPT to estimate memory requirements of a brain simulation, with neurons from a paper linked in OP post ("Single cortical neurons as deep artificial neural networks"). This paper uses neuron models that are supposed to simulate real ones. The answer was 8-50 PB, with 10^7 weights shared between neurons, or 3.4 EB if each neuron has its own 10^7 weights. So it's not out of the realm of possibility.