That might be another option, but then you risk the car getting stuck on its way to the customer. Also, I want to be able to Uber home from a bar drunk like an idiot, or take an uber because I can't drive.
I definitely see a place for share pool cars that deliver themselves to you when you need them and return autonomously when you are done, but maybe not Uber?
Would this mean that the "driver" seat is an open seat (intentionally leaving the accessible the controls)? This seems interesting, but legally would this be problematic? Who is at fault when the malfunctions and the user tries to help yet the accidental is most likely unavoidable given the disconnect between being the driver and being the stand-by driver? I would think that your reflexes and lack of actually controlling the car would be harmful to reaction time.