The problem here, the great limiting factor, is volume. We have finite volume to occupy things with and these carts would be way less efficient than a bus. Bus

The problem here, the great limiting factor, is volume. We have finite volume to occupy things with and these carts would be way less efficient than a bus. Bus drivers may be "expensive" but are entierly affordable in a public transport system. Hard to profit from though so america is fucked on that front. You're unlikely to see it without cultural revolution. Doesnt make proposed solution any less bad, or prone to simply perpetuating the ecact same issue plaguing the system now. as for fsd busses, much more feasible with public infrastructure as you can give the bus eyes via cameras mounted at any difficult points in the city, things hard to make privately accessible due to abuse but fairly reasonable for a well made and maintained publically managed privacy focused system.