They are also "discrete", which kind of gets in the way of modeling continuous processes in this case. And not very good about modeling trillions of things at the same time due to communication overhead (both latency _and_ energy). And all of that is the "easy" part. The hard part is we don't even know what the system needs to look like.

Yann LeCun said decades ago that in spite of all the progress there won't be anything artificial that's as smart as a rat in his lifetime. In 2021 that bet is still a safe one.