Well... depending on who you source, the majority of people already live in urban environments. In the US, the most recent figure from the census is 62.7%, which is more narrowly defined at % of population living in cities[1]. If you count "urban areas" which includes towns and villages, it is north of 80% [2]
Worldwide, we are at ~54% living in cities. [3]
This trend seems to be continuing globally as well [4], so pretty soon people in non-urban environments may have no choice (assuming, as I do, that cars will get more expensive as they have more and better technology and are much more highly utilized due to sharing)
No choice? In rural environments, where you have to drive an hour to a small city and 3+ hours to a large city, and there are no local businesses, no one is going to be operating self driving cars for hire. Electric cars aren't currently practical in such places either, though over time that will likely change as battery and charging tech improves—but I don't see shared ownership or commodity car usage replacing ownership rurally at any point, and there will always be people living rurally. If new cars stop becoming available at a reasonable price to buy, then people will continue repairing, rebuilding and using old cars.
Seems possible that as automation of delivery services becomes more widespread (e.g. drone delivery), and as both remote work opportunities and entertainment technologies increase, there will be less of an incentive, or at least less of a financial/work-related incentive to for populations to accrete around centralized urban developments. So the growth of urban vs. rural or suburban population rates may potentially slow in a few decades. Maybe, but probably not, idk.