I think it's still a reality, but just needs to be implemented differently. Something similar to how railway works, that is railway has infrastructure for train

I think it's still a reality, but just needs to be implemented differently. Something similar to how railway works, that is railway has infrastructure for trains and nothing else, but at the same time there are crossings for interactions with roads and train stations for interactions with people. When we have a place for self driving cars you can drive onto and have our car switch to automatic, it frees up a lot of the problems you need to solve. We can control the traffic more like a network then by having nodes at various intervals that conducts the traffic allowed on the route. This removes the need for the car to take on the responsibility of being aware of its surroundings. The same could be implemented more cheaply for passenger (arial) drones.