It's not that it would be terrible, but in the real world people are generally lazy and will only do what they actually want to see happen. Surprisingly, we don't yet have magical AI robots that autonomously go around turning all imagined ideas into reality without the need for human grit.
Since nobody really wants passenger rail in the US, they don't put in the effort to see that it exists (outside of some particular routes where they do want it). In many other countries, people do want board access to passenger rail (because that's all they can afford), so they put in the effort to have it.
~200 years ago the US did want passenger rail, they put in the work to realize it, and it did have a pretty good passenger rail network at the time given the period. But, again, better technology came along, so people stopped maintaining/improving what was there. They could do it again if they wanted to... But they don't.
Since nobody really wants passenger rail in the US, they don't put in the effort to see that it exists (outside of some particular routes where they do want it). In many other countries, people do want board access to passenger rail (because that's all they can afford), so they put in the effort to have it.
~200 years ago the US did want passenger rail, they put in the work to realize it, and it did have a pretty good passenger rail network at the time given the period. But, again, better technology came along, so people stopped maintaining/improving what was there. They could do it again if they wanted to... But they don't.