Yes. The evolutionary arguments seem clear enough. That isn't very interesting, though; how soon is it going to happen?

The only reason it might not be interesting is because it's clear; the limit case is certainly more important than the timeline.

That said, I mostly agree. The only reasonably likely third (not-singleton, not-human-wages-through-the-floor) outcome I see would be a destruction of our economy by a non-singleton existential catastrophe; for instance, the human species could kill itself off through an engineered plague, which would also avoid this scenario.