I think the biggest impact is going to be felt with current generations of 18 year olds. My kid (about to be 18) has no interest in getting a driver's license and neither are any of his friends. He's happy to be taking Uber and Lyft anywhere he goes. And between the cost of the vehicle and insurance, it's cheaper for me as well. When I was 16, I couldn't wait to get a car.
Vacations and weekends would be even more limited.
I certainly get not owning a car, especially in a city. That's basically a decision about economics and hassle. But even the couple I know who live in SF without a car use rentals and Zipcar all the time (in addition to Uber/Lyft).