In Spain, a similar length high speed train route would be Madrid-Barcelona, that's 400miles and takes 2h 30min.

If you offer me the same price for flying than for taking the high speed train, I'll take the train every time.

In practice it'll take less travel time, no security lines or theater (no problem bringing your water bottle or whatever), you can bring more luggage, you can stand up/walk/visit the bar during the trip, you go from city center to city center so you don't have to spend an extra in taxis... I just arrive there 20-30 minutes before the train leaves and that's all.

Oh I don't know — I travel the Boston-DC route a lot and fly only because it's significantly cheaper than taking the train. If prices were comparable I would take the train even without it being "high speed", I think there's a market for high speed rail if the prices were as low as flights!