This is very much true. Especially for private travel like city trips etc, I wouldn't mind at all if the trip took a little longer, for me the trip itself is part of the experience. But the prices for long-distance train trips are just insane. I can fly from the airport 10 minutes from my home to basically any city in europe for less than 100 euro, London or Paris often for less than 50. But a two-way train ticket to London for example could easily run over 400 euro's.

The problem is not so much with the price of train travel, even though I would not mind subsidizing it more so it could be cheaper. The problem is simply that plane tickets are way, way too cheap. I get that people like to fly and free market capitalism pretty much dictates making it cheaper is a good thing, but right now air fares are not including the hidden, socialized cost of air travel (pollution, noise, need for infrastructure, spoiling of touristic destinations, etc) of everyone being able to take flights on a whimsy just because it's so cheap. I would be fully in favor of taxing air travel heavily to compensate for these things, even more so if the proceeds could be used to make train travel cheaper.