We would run out of it very quickly

No. We wouldn't. The labor would simply be spent on that which people find important.

Nobody’s going to grow crops for you out of the goodness

Says who? PragerU?

That’s why capitalism exists in the first place.

No, Clyde... that's not it. Maybe don't extrapolate your politics from Civilization games, okay?

That has already been attempted several times

Yes, it has... and everywhere it was tried it was destroyed by fascists, capitalists and other power-hoarders because they were afraid it might work. For instance, Catalonia in the middle 30s and Ukraine in the early 20s.

Machines may yet solve this problem for us,

No, they won't.

and we’ve got the history to prove it.

Alt-history doesn't actually count as real history.