I think, though, that that's a tangential point, because Uber is not a car company. As others have theorized, Uber has an interest in developing it themselves because self-driving represents an existential threat. They have absolutely no defense against someone else using self-driving to do to them what they used gig economy labor pricing to do to taxi companies.
without the self driving vertical promises, uber is a middleman with a booking app, and they're one squeeze away from tesla or waymo into irrelevance.
Not many car manufacturer would market the airbags, breaks or tires as superior. However, car makers that develop their own engine constantly brag about how efficient or powerful their cars are compared to their competitors (e.g. Mazda and their Skyactiv, Toyota and their Hybrid).
If a company builds an autonomous driving capability and is able to hold on to a monopoly over it, they would either simply drive uber out of business, or license the tech to them in a way that would leave them with very thin margins.