Fast doesn't entail faster than a plane.
> the train would need to be more expensive
In my experience international train travel in Europe is always more expensive, sometimes 3-4 times more expensive, than airtravel. Due to subsidies and externalities. https://stay-grounded.org/privileged-position-revealing-the-...
Against your "almost nobody thinks like that" I and others described that we do think like that and personally know others who do too. I also posted two links that has some more general evidence against your claim. Your reply has some reason to lessen the weight given to that evidence, but not enough to cancel it. I rest my case until you present empirical counterevidence.
Your speculations/prejudice about motivations of others is not evidence and such stories can be made up in almost any direction e.g. maybe you delude yourself into thinking no one takes trains for environmental reasons because it makes you feel good and superior in thinking you know their motivations better than they do.