I think the self-driving efforts by the ride-sharing companies were just there to attract massive investment rounds. Now Uber's public and investors are generally aware that the level of self-driving required for autonomous taxis is decades away. Probably a good choice to sell.

But I thought that was the whole point of Uber, to replace their workers with AI right? I'm guessing they now are just going to attempt to partner with one of the winners of the self-driven-horse-race, but I'm thinking that if you are the winner of the self-driving-horse-race you don't need uber, if you can build self driving cars/software you can probably clone Ubers functionality and do your own app.

Probably for the best. Right now Uber is NOT among the leaders in self-driving. So it would be better for them to buy or lease vehicles from those leaders than wait some additional years for their own project to be successful.