Are they profitable? Last I heard they were losing quite a bit of money. [1] And even if they manage to squeak out a GAAP profit, I'm not sure if the business is sustainable. Given that a lot of the capital and operations costs end up on the books of drivers, it's harder to do the math for an end-to-end costs-vs-benefits comparison.
[1] https://www.reuters.com/article/uber-results/uber-narrows-lo...