I still think that we will move to some sort of subscription based package;
"ou'll pay based upon what type of vehicle you want to use, when you tend to use it, the locations, and how long you want to wait for a car. Those that don't want to wait pay more; if you can wait half an hour, you'll pay less."
The only time I thought this had a real shot at working was the home/office/home commute. It's the most common journey and I could see you could justify a 1 person vehicle tightly tailored to your personal environment IE cup holder, decent radio, jacket hanger etc.
I figured they'd be delivered by 1 driver in a train that would drop off the end vehicle and self park ready for its driver of the day. After the driver parks it it's then collected, washed and cleaned (or used by shoppers to come from their shopping) before dropping it (or one just like it) back in time for the drive home (and recollection).
But the rest of the time I don't think people want something that anonymous. They want their vehicle, their way, in their colors, parked where they left it.