It's a cop out in my opinion, it will never scale or be as useful , reliable or enjoyable to use as a well designed, operated subway. Besides Tokyo, Shenzhen, Beijing etc, will have both, subways and driverless, flying taxis, drone delivery and still be ahead of most major US cities in terms of transport options.

You have to visit a top tier East Asian city to understand just how good they have these things running, safe, clean, reliable, always on time. Like, it's amazing. Uncomprable to anything I've experienced in any major US city.

I think if a New Yorker went to Tokyo they'd be amazed how far ahead they're public transport is.

There are also health benefits to using public transport which I think we will see play out with self-driving, people will just become slobs when a car comes to their door, picks them up and drops them at the next door. Using a subway is actually a bit of healthy exercise.