NYC people uses it because the alternatives are either slower or much more expensive. I'm sure they'd rather use a waymo if it was as fast and cheap as the subway.
Using Lyft, Uber, or Waymo in San Francisco is slow, especially during peak times. To go across town in NYC by train, it would take 5-10 times as long to go that same distance in SF by car. If you have to cross a bridge or tunnel, it's going to be even longer during peak times.
That's the whole problem. Car transportation simply doesn't scale, so there will never be an option to use waymo that's as fast and cheap as the subway. It's worth calling out that an efficient train system is vital to keeping car traffic moving quickly, because once everyone is in a car, it's gridlock.
