>The best (short-term) case is that they become eternal parasites.

Producing a product that delivers value and people are willing to pay for makes you a "parasite"? Sure, it might cause massive disruptions to the labor market, but that's mostly orthogonal to whether it's a "parasite" or not. Mechanized farming has almost wiped out agricultural employment (compared to pre-industrial levels), but that doesn't make tractor manufacturers or fertilizer companies "parasites"