Rail is still slow compared to flying. Really slow.
Trains back in the day of heavy rail use didn’t go 150 miles/hour, but they were still pretty fast. It was common for passenger trains to go 70 mph. But I recall reading an ad for a luxury, straight-through train from Chicago to San Francisco. You got on the train on Friday evening and “presto” you arrived in S.F. on Sunday. So cut that in half and it’s still slow.
I agree that urban sprawl makes mass transit impractical. It wasn’t just a matter of subsidies. I have a photograph of men digging the utility lines along my grandparents’ house. There was an army of them with picks and shovels. Water lines go deep and sewer lines go even deeper. Now, you take a backhoe and dig out in a morning what it would have taken those guys days to dig.
And too, the water towers are massively larger and higher, and the pressure is much greater. Developers can reach a lot farther out, more cheaply, than they could 100 years ago. If you look at old sections of almost any town, and you see that the houses are very close together. That’s largely because putting in utilities was so daunting.
People obviously prefer larger lots if they can get them. Stores are much larger and farther apart. I think it would be extremely difficult to establish effective mass transit in a lot of places. My brother lives in the Kansas side of Kansas City, and that widening of spaces has taken on proportions that surprised even me. Commercial establishments are on gigantic, heavily landscaped “lots” that are bigger than city blocks; acres and acres. Stores are in a different section altogether, with lots of space. The residential areas are miles from places where people work. The design, I guess, is to give a “wide open spaces” look to it; a more “natural” kind of environment, and they sure achieved it. If cars become too expensive to operate, there are going to be a lot of people on motorbikes because you couldn’t possibly get around in that place without individual transportation.