In my town, Uber absorbed a bunch of the travel, public transport was cut in half, and now with gas and other expenses no one can afford to run Ubers up here. Maybe one car around, often a 20 minute wait. Car pool services cannot fill the gap.
I don't live in an area that has Uber, so I'm not that familiar with it, only used it a few times when traveling :)
My impression of the the way drivers are compensated is that the hours, fuel, and wear on your vehicle make it kind of slim margins.
Other than when Uber deeply discounts to drive growth, it's always been cheaper to drive yourself than to pay Uber. The reason you pay Uber is for other reasons (e.g. convenience, cost of parking, being away from your vehicle, intoxication).