The issue brought up though, is that robocars might make the sprawled and unconstrained city appear almost as "livable" as the one that had the density due to c

The issue brought up though, is that robocars might make the sprawled and unconstrained city appear almost as "livable" as the one that had the density due to constraints (or history.) People moved to the burbs not for love of sprawl, but for love of larger lots, larger fully detached homes, quieter streets and also (though not as inherently) lower crime and better schools. They largely do it for their kids. The car didn't make them move to the burbs so they could live a car lifestyle. The car allowed them to move to the burbs. But a world where transportation time is always productive, and you always get dropped very close to where you are going with no parking hassle will be different. (Like a taxi filled city such as Manhattan, but much better and probably cheaper.) What if there are still cool, walkable pedestrian blocks of shops and restaurants and active life, but you can live 3 miles from them and still enjoy them the way that the people who live 4 blocks from them enjoy them today? One fear you might have is that these things may already have a name -- malls. Except malls are covered, and privately owned and thus somewhat sterile, but people also seem to love them. But what if any suburbanite could be delivered to the car-free mall to wander at any time for $1, delivered right inside (not to the parking lot, which it doesn't even need any more) and while able to make full use of that 10 minutes reading books or watching videos or working? How does the "livable city" compete with that in most people's minds?