Is that realistic, though? A car is already a status toy, what's to stop conspicuous consumption in the form of buying one's own self-driving car? Or, say, moving to a cheaper house further from the city, because commute time can now be used as work time? Shared cars won't work in that scenario.

Also, rush hour is still a thing. There have to be enough UAVs to handle peak demand, and then most of them will be parked somewhere, idle most of the time. Or running errands. Traffic congestion is bad enough now, with average vehicle occupancy of 1.2 people; it'll be apocalyptic when that number drops below one.

Also, in cities with sky-high housing costs, i guarantee that people will live in self-driving RVs, because road space is "free."

In short, the only way to realize the benefits of the shared UAV future is to ban private car ownership, and cap the number of UAVs in a city. That sounds a lot like a train, except trains' enormous capacity offers better service.