Early passenger trains were more of an advertisement for freight companies. With the growth of airports, it just became uneconomical. People praise the Russia system but it's pretty highly subsidized. AmTrak and Australia's passenger system are about equal really (except in Australia you can pay to put your car on a carrier if you're moving cross country).

It's partly a federal funding failure for AmTrak (a funding failure a few of those $5 billion payments to Israel could have fixed) and party a density issue. Florida does have high speed rail now, which is pretty amazing considering Caltrain's high speed network went billions over budget and never really got started.

Several companies talks about a high speed from Nashville->Chattanooga->Atlanta, but the people shot that down pretty quick. No one wanted all those commuters.