Too many American city centers aren’t really set up for non-car usage, so even if cars went away, people would need to walk pretty big distances to get to where they’re going. Modern American cities need to be fundamentally redesigned to support a car free or reduced system.

I realize you're talking about the current feasability of non-car transportation, which it sounds like we all agree leaves something to be desired.

Banning new modes of transportation is really just going to reinforce the existing car-centric design of cities though.