Poland is approximately the same geographical size as Nevada. In the US, "between cities" is more like New York to Las Vegas, not Las Vegas to... uh, I couldn't think of another city in Nevada off the top of my head. What under-serviced route were you thinking of there?
What gives you the idea that rail would be preferable to flying for the NYC to LAS route if only it existed? Even as the crow flies it is approximately 4,000 km, meaning that at 200 km/h you are still looking at around 20 hours of travel in an ideal case. Instead of just 5 hours by plane. If you're poor an additional 15 hours wasted might not mean much, but when time is valuable?
What gives you the idea that rail would be preferable to flying for the NYC to LAS route if only it existed? Even as the crow flies it is approximately 4,000 km, meaning that at 200 km/h you are still looking at around 20 hours of travel in an ideal case. Instead of just 5 hours by plane. If you're poor an additional 15 hours wasted might not mean much, but when time is valuable?