That is it, and the ability to use the data to start offering sharing options with either discounts or priority pick up to make people ride share when capacity is full will be a massive change ("we're seeing high demand; you can wait 10 minutes for a vehicle to yourself, or a ride share can pick you up in 5 minutes"). There are plenty of times where I know it will take time to get a car because of demand, and would happily share if it meant I'd get picked up sooner.
Smoothing that out, so that you come to expect a car to be available very rapidly no matter what, with only minor inconveniences, may not end private car ownership but certainly will make a lot more people opt for alternatives - I know for myself (I don't own a car) the occasional lack of predictability in how soon I'll get picked up is the one aggravation that occasionally make me want one.
the bike shares solve this by driving trucks around, collecting bikes from areas where they aren't going to be needed and moving them to areas where demand is about to spike. it's hard to load up a truck full of cars to meet demand in the business district at 5pm, but it's very easy to send over all the spare capacity in your autonomous vehicle fleet.