They're not losing money on rides.
Uber is two things. A moderately profitable ride sharing company, and a loss-making VC-backed R&D enterprise working on things like self-driving cars. If they shut down or spin off their R&D they could continue on as a ride sharing company indefinitely -- they could probably lower prices because they're not using that money to supplement the VC money they're spending on R&D.
But you only separate the R&D if you think it won't ultimately lead anywhere. If they eventually actually get self-driving cars working then it's obviously to their advantage to be the same company that people are already using for car service.
