It's quite the opposite: I am not "just" disagreeing with you. I agree with you but think you've used a bad example, a bad argument, and no logic to make a claim I would otherwise support.
The Acela definitely manages to sell tickets, my point is: it's not necessarily your average joe. (I'd like to think a half hour of my time is worth 50 bucks, but more often than not -- most of these trips will be for recreation -- it's not.) 20 years from now the train may be done and most people will still probably choose a flight or driving because the cost versus time saved isn't that great for the vast majority of people.