Not parent but I read this as an answer to GPs question: “what coercive power does Uber wield that allows them to exploit workers all while non-exploitative employers have struggled to find anyone to hire?”

Hiring during a recession is not in and of it self any more exploitative then hiring during an economic up swing. However, during a recession you can easier get away exploitation which you wouldn’t have gotten away with if the labor conditions were better and the jobs were plenty. This is what Uber exploited.

I will add to that that Uber also played with the psychology of their workers, exploited addictive behavior by “gamifying” the work. This creates a cognitive dissonance among the worker which “tricks” workers into accepting conditions they otherwise wouldn’t have.