Perhaps having an opaque, complex pricing scheme isn't great for customer service or public perception of the company.
Amazon tried this a few years ago, and I believe they stopped doing this but I'm not sure. But if I knew or suspected that Amazon was trying to squeeze a few percent from me, it would make me less inclined to use them. I can't see how this isn't the case with Uber as well, if customers suspect they are being gouged. It would then open the doors for vast accusations like the twitter post.
You just don't notice because they get replaced, and the new people assume that existing practices are the norm. The world keeps spinning.
I guess my point is, if you don't see many people leaving at once, that isn't evidence there isn't something fishy going on. People have families, mortgages, children's tuition payments...