[Kaiyou]

Post-scarcity doesn't solve the fundamental problem of earth being unable to sustain infinite humans. Even with infinite resources, there will still be finite space.

Historically, human populations that did grow beyond sustainable had to starve to death back to sustainable. If you prevent this by giving everyone free food, that's not really a good thing.

[devit]

Yes, but this is solvable by limiting the number of children per person.

[Kaiyou]

That's how you get stagnation. It's also rather unfair.