> an AI doesn't actually need to be able to perfectly replace the work I do for someone to decide that it's more cost-effective to fire me and give my work to that AI.

Exactly, "lack of intelligence" is really a much bigger concern than "superintelligence". Companies and government will happily try to save money and avoid accountability by letting AI do work that it can only do poorly and it will be humans who are left with the accelerated AI powered enshittification and blind/soulless paperclip maximization that results.