People in Europe take trains because it's a better alternative than driving!
Make subways land right in the train station in SF, then make the train faster, then you have something useful.
On the other hand I agree with the premise of the article. If you have high mobility in a state, the state will become reacher. Doesn't make sense to wait for national trains to be a thing, make sure people can easily move across your state without having to rely on having a car.