A lot of those benefits can be had from taxis - and yet people still buy their own cars.
Another model are shared cars, like dockless scooters and bikes. They are reasonably popular in the Netherlands for example. But they still require quite a bit of planning to ensure the car is available, and they are not always "in front of your door". Also you need to rent it for the entire time that you're away.
Irrespective, SDC will take some time. Like NLP, they work will within a constrained problem domain, but don't really generalise.
Mind you I live in a rural area and spend a fair amount of time (1 day week) in areas with no or very poor mobile phone coverage so that might put me off!
Human driver's only account for 50% - 55% of a cab's cost.
https://urbankchoze.blogspot.com/2014/08/what-taxis-can-tell...
https://www.quora.com/What-is-the-breakdown-of-where-taxi-fa...