Wouldn't it be ironic if, after all this, it was discovered that the most economical way of producing some fundamental 'unit of intelligence' was to feed/clothe/entertain a human?

This is the very core of my issue with "AI". From a resource usage point of view, it cannot hope to compete with a developer armed with a banana.

Ook.

You can always put the brain in a jar: https://corticallabs.com/cl1.html

Isn't that the premise of The Matrix?

Bar "clothing", I guess.

It would be. But that's not going to happen.

No, that is just equilibrium economics.

Machines are cheaper than humans? Buy more machines.

Humans are cheaper than machines? Hire more humans.