This is a silly hypothetical. Chances of it happening are almost nil.
Personally, I’m not holding my breath waiting for autonomous cars to take over the roads. The best technology currently out there requires a huge array of sensors to be able to navigate safely, and still have problems if visibility is limited (especially if the sensors are obscured by snow and ice).
When you hear people saying that self-driving cars would be more feasible if the lines on the road were painted better, you know the technology is not ready for prime time. If it isn’t at least capable of handling the same variety of conditions and situations as an average human driver (and the average driver is not very good, and they still have no problem figuring out where the road goes if the lines are a bit sketchy), then it’s not ready for the road.
But yeah, when it does come, we probably won’t own the cars anymore. They’ll be too complicated and expensive, with serious maintenance requirements, and liability concerns, that only corporations or maybe public utilities will be able to operate them.
That is, unless someone manages to produce real AI sometime in the next couple of years - AI that can really understand what it is seeing, rather than just running mindless algorithms.
I have heard that the business model will be for Ford or GM or Toyota to manufacture and retain ownership of a whole fleet of cars. Individuals will then buy a "monthly subscription". Your subscription tier will then allow you a certain amount of miles, in a certain class of car, either carpooling with other riders or privately. Maybe your subscription will allow you 500 "Ford credits" per month. A last minute, 5 mile, private trip in a luxury vehicle will be 10 Ford credits while car pooling, advance notice or older more economy vehicles will reduce the charge to 3 Ford credits.
If you need to go to the grocery store or to work or to the hardware store you will just pull out your phone (like with Uber) and order a car (or truck or van). It will show up in minutes and take you to where you need to go. No need to worry about parking, fuel, insurance, maintenance, accidents, etc...
There will certainly be limitations on privacy and independence that come along with the convenience. If the service works as described, I am thinking that people will gladly pay $100-$500 a month for a subscription to such a service.