>There are plenty of people who haven't figured out how much money they're going to end up spending on vehicle maintenance as a result of all that extra driving.
The IRS mileage rate is supposed to be an average cost for operating a vehicle. It is 53.5 cents per mile. Uber pays about twice that per mile in San Francisco. So if you can go at 60 MPH you'll be making about 30 bucks an hour, which is not bad for unskilled labor.
(1) You're assuming all miles and hours are 'billable', while in reality you would be driving empty towards a pickup and waiting for the next pickup.
(2) 60MPH in San Francisco is going to get you some pretty bad fines most of the time
So, let's assume you spend every hour waiting for 10 minutes, driving 30MPH to the pickup for 10 minutes, and driving a customer at 30MPH for 40 minutes, your average hourly gross income is 20$ (40/60*30*1$) and your expenses are $13.375 (50/60*30*.535), giving you a real income of under 7$ per hour. Good luck finding a house and food for that in SF area...