With a self-driving car, it's not them driving it. It's the car. Just like when you;re in it, except they leave trash on the floor.
Self-driving cars take Uber to a new level - no driver, no unavailability. You're not the driver, so why does your Uber client need one? No unavailability except for when you have a scheduled trip (coming home from a concert...).
The only needed human intervention is refueling. Until they self-park on your charging mat, or park and hit the charging plug.
Maybe you don't really buy a car alone. Buy into a consortium, several other 'owners' nearby, so if you want to run out for a pizza you can either have it deliverd by Uber or ask for a local car and get out of the house for a bit.
Did you hear that, Amazon? Skip drones. Figure out self-driving car consortiums. Uber + shared self-deriving vehicles + Jet Amazon home delivery Amazon at all.