In self driving world it no longer makes sense for a car to look like they do now.
Instead I think they operate a bit like Coach and Horses used to. You the consumer own the "coach", you have it specced out how you want it, your choice of seating (hell even a bed?), your sound system, your big screen tv, whatever you want because you're a passenger not the driver.
The "horses" are the self driving bit + batteries. The ubiquitous taxi service owns these. Maybe you permanently rent a low range model (100 miles) that is attached to your "Coach" at all times for quick errands. For longer range journeys you hire a model with more battery and longer range that drives over and attaches automatically to your coach.
For really long range journeys, your self driving "horse" drives into a coaching station along the way, detaches and another one attaches in 30 seconds and off you go.