I should admit that I drove for only a month but I also have known quite a few longer-time drivers. And in my defense, the industry was setup so most people stayed for that short time and only a few people, who actually bought their cabs, stayed for longer, literally ate and slept in their cars and made a chunk of money over, who knows, five years but also quit but in better shape financially (and worse shape physically, I'm sure).
Was in an uber once, driver told me he did 14 hour days and was very happy with the money he was making. From memory, 4k £ (UK) though maybe I misremember.
14 hour days, eh? I didn't ask if he thought that was safe. Uber should never let that happen but clearly they were ok with it, or with carefully not looking.