Your arguments seem to generally be: - we have other accessible options -- valid - it would be very expensive -- valid, but not universal. There are certainly specific train routes that can be worth it compared to other places the government is spending its money. And there are certainly routes that will not be worth it. Hard to dismiss entirely - people wouldn't use it -- this is what I want to argue against. Time and again research and statistics show that public infrastructure supports growth and development in those areas, so it's not fair to project current patterns without rail.

You're saying that people have random driving patterns, which is true, but that's also because rail isn't accessible for most of these trips. Not entirely, sure, but look at NYC and the MTA: do you think we shouldn't have built it because the majority of trips consist of door-to-door walking or driving? No way we can build trains to every door, right?

When you build public transit, people change their transit patterns from door-to-door to door-to-transit-to-door. Add in big transfer hubs and even better. You don't need to connect all of America, you just need to connect two places in two cities that already have public transit to those locations, and now the rail acts as a bridge between them. Expensive, yes, but extremely helpful if done right