I mean in London the fastest option is public transit more often than not, and you get pretty close to door to door.
People "prefer cars" because people prefer detached houses and low-density living. Not all of them, but plenty enough. For them, an EV is the only electric option.
In cities, of course, public transit should predominate, and should be developed and improved, while car presence should become lower and lower.
it's fine if people use ICE vehicles now and then to visit family, go to a specialty store, etc. it's the daily and weekly trips that need to be fixed.
and the breakeven point does not need to be quite so dense as London. for example, the DC area has a lot of sprawly (at least by east coast standards) suburbs. the DC metro has some room for improvement, but it is still much better than a car for getting into and out of the city during peak hours. though I'll admit I sometimes splurge for an Uber. cars are much more competitive when you don't need to park them.
Obviously it wouldn't scale that well for everybody but I wouldn't be surprised to see, if self driving cars master Manhattan, some more well-off people who aren't currently at "private driver" level of rich to move to self-driving cabs or such to avoid crowding and go point-to-point.
The big advantage of the trains was in leaving Manhattan and going to Long Island, though, compared to the car-bottleneck-hell of the bridges and tunnels.