The younger generation is using cars less exactly because driving/parking/owning a car is expensive and a hassle, not because they suddenly prefer watching bums on the subway to watching Netflix alone. Choosing between Uber and shared public transportation is a question of cost, and self driving cars will get the cost down so it's much less of a factor. In all the countries where the share of public transportation is significant, the main reason is economical. Gas is more expensive in the EU, free parking is scarce, wages are lower, etc. Actually walkable cities help, but it's not like europeans couldn't find a use for a car if they could easily afford one. Or how about private car ownership growth in China [1]?
The other point is that American society is pretty well-segregated, and personal cars and suburbs ensure there's minimal contact between the classes. Unless your shared car service has tiers that allow that segregation to continue, a significant amount of people won't use it. Physical security is a part of the equation - you're probably not getting sexually assaulted or burgled in a personal SDC.
On renting vs owning: again, it doesn't matter - if the cars are not shared, this doesn't really affect the traffic volume (driving between drop-off and the next pick-up are empty miles, but that's hopefully insignificant).
> In all the countries where the share of public transportation is significant, the main reason is economical. Gas is more expensive in the EU, free parking is scarce, wages are lower, etc. Actually walkable cities help, but it's not like europeans couldn't find a use for a car if they could easily afford one.
No, the main reason is government policy, most obviously in town planning. There's simply no place to park, and enough traffic that the journey is neither fast nor relaxing. The result is that people who could easily afford to (e.g. my friends working at Google or Facebook, or in finance) don't own cars, and use public transport to get to and from work.
Walk round the suburbs of European cities on a weekday, and you'll see lots of parked cars, in rich and poor areas. People own them, but don't find them the best way to get to work. They use them at the weekend.
The other point is that American society is pretty well-segregated, and personal cars and suburbs ensure there's minimal contact between the classes. Unless your shared car service has tiers that allow that segregation to continue, a significant amount of people won't use it. Physical security is a part of the equation - you're probably not getting sexually assaulted or burgled in a personal SDC.
On renting vs owning: again, it doesn't matter - if the cars are not shared, this doesn't really affect the traffic volume (driving between drop-off and the next pick-up are empty miles, but that's hopefully insignificant).
[1] https://www.eia.gov/todayinenergy/detail.cfm?id=16251