You still have a bunch of workers that used to produce something of value that required a certain amount of amount of labor that is now replaced by slop.

A lot of the applications of AI specifically minimize worker involvement, meaning the output is 100% slop. That slop is included in the training data for the next model, leading to a cycle of degradation. In the end, the pool of human knowledge is contaminated with plausible-sounding written works that are wrong in various ways, the amount of labor required to learn anything is increased by having to filter through it, and the amount of waste due to people learning incorrect things and acting on them is also increased.