I understand this scenario, but outside large cities it is not nearly as attractive. I think public transit also can fill a lot of this niche if it is run properly.
Some people just want easy transportation to get them to their destination. The Johnny Cab type door to door service could become very inexpensive, so there is no reason to take on the overhead of owning a vehicle. This type of service works very well in densely populated areas very well.
Other people, like me, enjoy driving and live in less congested areas. An autonomous vehicle makes less sense. Again, for my commute I can choose to use the Johnny Cab, but for my personal vehicle I want the freedom to go on more back roads etc.