There isn't really much political will to mitigate car dependency and curb sprawl, but if hypothetically there were, it would still take half a century of concerted effort to reshape our cities into something a little less dystopian, and in that meantime autonomous vehicles would be very effective for shuttling people between their homes and major transportation hubs, because busses on feeder routes just don't work very well out in the burbs.

This has been modeled and studied extensively by the car companies to understand market sizing in a fully autonomous world. Everything points to a rather dramatic reduction (integer factor) in the number of cars on the streets, which needless to say is a dire outlook for those businesses.

The Segway was banned from San Francisco sidewalks almost immediately upon release. You really think NIMBYs are going to sit quiet as the streets fill up with empty cars circling like sharks?

As many cars as concurrent rides the market demands. There's always an upper limit.