For any increase in passenger rail, there would have to be a fundamental mindset change in the average person as well as a fundamental redesign of our cities and towns. In Europe, especially Germany, where I was stationed for a year, cities were built long before the automobile. Most lived within the city walls for protection and convenience. Every neighborhood had its own market, drug store, hardware store, etc., as did most neighborhood dwellers work where they lived.
With the invention of the automobile, people weren't tethered to living where they work. They could live on one side of town and work on the other. The commute would be via bus or rail or subway, since the small streets and hodge-podge design of the city aren't conducive to moving large amounts of cars for any real distance (not to mention parking). Towns that are laid out in compact fashions in the US (ones that were founded and well-established before 1850) benefit from a developed public transportation system. However, I'd say most of the country does not have such cities and towns, and thus are spread out greatly.
A trip from the town I was stationed in to Munich was about 45 minutes, via rail or car. The car had the advantage that I could leave from where I lived rather than walk a mile to the hauptbahnhof, and then catch the train. However, if I was going to the Munich Airport or altstadt Munich, then riding the train was better since I didn't have to worry about parking a car or traffic.
Occasionally, though, we'd go up to Wurzburg, about 4 hours by car, because we'd go shopping at the big PX there. You also wanted your car so that you'd have a way to carry back everything you bought. I wouldn't have been able to go from the kaserne to the train station and then 4-5 hours back to my post with more than a six-pack of Barq's rootbeer via train, as it involved changing trains at least once.
Even with the famed Autobahn system, the train is easier to go from large town to large town, because of the amount of truck and car traffic congestion. The distances covered by the TGV, ICE, etc. also don't equal the same distances here in the States. In the US, 4 hours by car could get me almost 300 miles without stopping. 300 miles in Europe by car is an overnight trip.