But in most cases, you aren't buying a car just to drive for Uber (more than half drive between 1 and 15 hours a week [0]), you're doing it on the side. Your per mile costs for driving for Uber are the marginal costs (costs of additional insurance, fuel, marginal wear and tear, etc).

Also, if you're driving for Uber in a new car that gets 17 mi / gal fuel efficiency, you're not making wise moves. There's a reason a lot of Uber drivers are using 5 year old Prius's - this cuts the fuel cost in half, and the depreciation down quite a bit.

[0] https://www.vox.com/2018/10/2/17924628/uber-drivers-make-hou...