Autos will never be sold to consumers. At least the general public. Or at least average people will never buy one.
It is a tremendous, insane, unacceptable waste to have autos parked all day. The only way these things make sense is through subscription services where you can summon a car from a fleet whenever you want, so that you can maximize utilization.
However, the reason for that is that the majority of people keep roughly the same hours. And the current system at least has the advantage that cars are generally near their owners rather than driving additional miles to get to centralized locations. Given various assumptions, utilization could certainly be increased--though we already have the ZipCar and taxi options--but I'm unconvinced that the pay-per-use economics are going to be as compelling as you think.
Except it is a self managing fleet. Autos would not just stay in central locations, they will use current parking infrastructure to distribute themselves. People will have drive ways for a hundred years even if everyone gets rid of the cars - and you'll get 5% off your subscription to let them park autos in your drive way.
And the majority is just maximal utilization. Even then, it is drastically less than the total number of vehicles in the system, and the reuse of those vehicles every other hour of the day besides peak hour is only a utilization gain.
It will be much cheaper to subscribe to an auto service than own one. In the best case one auto could possibly represent the vehicle usage of a dozen or more people if their driving times align properly. And the worst case is that it is still two or three times the utilization.
It is a tremendous, insane, unacceptable waste to have autos parked all day. The only way these things make sense is through subscription services where you can summon a car from a fleet whenever you want, so that you can maximize utilization.