$10/hour is a rough estimate for the after expenses earnings for Uber drivers. The gross Uber pays is more like $16/hour so that’s the number to compare if you are going to look at Uber’s all-in cost to run a fleet. Using the 16 hours/day estimate it comes out to $93k a year of driver payments saved, which seems like it should easily pay for the purchase and maintenance of a car (especially if the car lasts multiple years). Uber has access to capital so they can handle the “up front” nature of the expense. Paying people to drive a car around all day is expensive and if Uber could avoid that they would have a better business.