A social system that looks at a technology like LLMs and decides to use it to increase "output" in some abstract way while reducing the median standard of living is a system that will have a hard time maintaining popular (non-elite) legitimacy. That doesn't mean it will evaporate over night -- plenty of ghastly social systems have survived centuries with very little non-elite legitimacy.

It remains to be seen if LLMs will be used in this way, but the messaging so far (including your post, the one I'm replying to) suggests that the elites' inclination is exactly that: more profit, more control, more power now for elites, temporary (possibly years, maybe as long a generation or three) but real suffering for many of the rest, and a steady state at the end of the transition where they are still in charge, much richer, and maybe also everyone else is better off (if they can't capture the gains completely for themselves).