[shiroiushi]

That's why you have to build and live more densely. The US absolutely refuses to do that, outside of Manhattan and a few select other places. It won't be a place where local trains make any economic sense until this changes.

However, for your "door to door" point, that's not desirable anyway. Even here in Tokyo, you have to walk a lot to get between your home and work or wherever you're going. That's a big, big part of why people here are so much thinner than Americans. Having transport that takes you door-to-door without any significant walking is terrible for your health.

[minwcnt5]

Tokyo has taxis and Ubers. I take them quite frequently when there, even though the public transit is amazing. The fact it's blatantly obvious that robotaxis make a ton of sense in even one of the most transit-friendly cities in the world shows how wrong the OP is.

[shiroiushi]

This is true, but taxis in Tokyo are expensive; they're not affordable on a regular basis to most people.