Highspeed trains need special tracks. Creating these tracks involves confiscating a lot of land from people along the way.
Roads also need a lot of space. So I don't entirely see your point. Maybe roads need 20% less space or something, but it's not like they need no space.
Doing this creates many lovely opportunities for corruption in government as the route can go a lot of ways depending on who influences it.
We have solved huge parts of that in Europe. We do it with open goverment, post journals showing mail that has arrived to a government agency, political hearings were everybody can send in their opinion, and the agency has to comment and publish all hearing comments. This mostly works. In the cases where it doesn't work, a sufficiently pissed of party can take the case to court to have the process reviewed.
"It says something about the state of train travel in America" yeah it sure does. It says that people would rather drive than be subject to that TSA garbage.
Straw man. We don't have TSA garbage on european high speed railways. And while I can take the train for long distances in the Europe, I believe I'd be taking a plane in the USA, exposing me to that very TSA garbage.