According to the Q1 reports, rides are actually profitable for the company. They just lose money on other segments, like Eats, and spend an absolutely massive amount of money on "platform R&D" (many hundreds of millions per quarter).

https://investor.uber.com/news-events/news/press-release-det...

(not I am using Q1, because Q2 has been an... atypical quarter for this sort of business)