Except that the only choice for rail (Amtrak) takes twice as long as driving at the best of times. For short trips, you might as well drive. For medium distances (10 hours driving), your travel time balloons to over a full day in most cases. For long distances (cross country), you pretty much have to fly.
There's just not a place for rail to fit in.
% "Every morning, I get up and look through the 'Forbes' list of the richest people in America. If I'm not there, I go to work" -- Robert Orben