A human neuron is a thousand times bigger than a transistor.

There are directions hardware and algorithms have been going in - parallel processing - that are not limited by fabrication?

> A human neuron is a thousand times bigger than a transistor.

Correct, it works on principles currently completely unapplied in ASIC design. We don't, for example, have many mechanisms that allow for new pathways to be formed in hardware. At least, not outside of highly controlled fashion. It's not clear that it would even be helpful if we did.

> There are directions hardware and algorithms have been going in - parallel processing - that are not limited by fabrication?

They are limited by the power budget. Yes we can increase the amount of parallel compute 100x but not without also increasing the power budget by 100x.

But further, not all problems can be made parallel. Data dependencies exist and those always slow things down. Further, coordination isn't free for parallel algorithms.

I'm not saying there's not some new way to do computation which hasn't been explored. I'm saying we've traveled down a multi-decade path to today's compute capabilities and we may be at the end of this road. Building a new model that's ultimately adopted will (likely) take more decades. I mean, consider how hard it's been to purge x86 from society. We are looking at a problem a million times more difficult than just getting rid of x86.

Transistors will never reach the efficiency of a neuron. A transistor is too limited in it's connections.