That Uber can keep doing that (requiring 4.5 star averages) could be a symptom of a power imbalance: there is a huge surplus of qualified and willing potential

That Uber can keep doing that (requiring 4.5 star averages) could be a symptom of a power imbalance: there is a huge surplus of qualified and willing potential employees to them so they can be picky. That means that at the moment, there is less competition in the business than there could be (competitors could be nicer places to work, and hence could get by for example with paying less to workers, and be cheaper to customers as a result), or there are simply too much workers available compared to the amount of work available. It's probably some mix of those. I've also noticed that in low skilled jobs, there can be many companies with very different cultures, and people pick the one where they fit in. They might all pay roughly the same and they don't differentiate that much with their service quality, because there isn't that much to differentiate with. Despite all the talk about excellence, the customers are not willing to pay much for any cosmetic extras.