Well, we'll see what the future manufacturing brings, but right now we're not even at thousands of layers (as far as I know... please link if there's been more), and we'd need to be in hundreds of thousands range. Given the rate of defects also adding up and the need for some way to dissipate the heat... (almost all of that chip will be engaged while running - no chance for balancing power between systems) Yeah, still lots of challenges there.

(I'm assuming the original comment meant literally putting the network as is in the purpose designed chip)