>but at some point jobs evolve to meet new market demands.

Possibly. If you believe in the economic equivalent of directed evolution, then no matter what humans do, the economy will tip itself towards creating employment opportunities within the broader circumstances.

But if AI plays out the way some hope (and there's no reason to suppose this is impossible), then it will become a substitute (and likely a cheaper one) for every human employment there is. The economy will not evolve to make more jobs "somehow". We actually see this in evolution too, where some species or another without seeing any particular catastrophe just sort of withers away because bad evolutionary decisions made previously make it impossible to reach new environmental niches which might support the population. The so called "path dependence".