We don't put the TSA at the entrance of public parks either
Unless high-speed rail becomes successful enough to become a real option, in which case they'll be economically forced to pack customers in like the economy class on modern airliners, if not tighter, to maximize revenue.
> as a project that would likely be subsidized with tax dollars
... it's going to have to wait for enough of the Tea Party to die off before it's politically viable, and by 'Tea Party' I mean anyone who is primarily concerned whether every single cent the government spends can be justified through a purely Originalist reading of the Constitution unless the money is going to fund the military and/or the police.
I traveled extensively via Europe's high-speed rail network during the summer of 2012. If you didn't know already, rail service has been the primary mode of transport for long-distance trips in Europe for several decades. The coaches are still luxurious compared with airplane seating, and I could recline fully and get up to go purchase some snacks or a meal.
The thing with trains is that they are not space- or weight-limited like airframes. It is much easier to tack on a couple of extra cars for heavily-trafficked lines than to pack people in like sardines, and it makes economic sense to keep train coaches comfortable if you are advertising yourself as the luxurious alternative to air travel. Given the European and Asian models, I don't see evidence that rail services will be forced to cut comfort like we have seen with the airlines.
As someone who travels occasionally--albeit somewhat infrequently--for both business and pleasure, I share the opinion that flying is not altogether pleasant. From arriving at the airport several hours early, to dealing with TSA, to sitting in the cramped aircraft seating, it's not a stretch to say that it's a somewhat miserable experience. For the amount of money one has to pay for a flight, especially if going to a less popular/metropolitan destination, the experience is very sub par.
Trains, however, are a joy to ride. There is no TSA (or any other form of security theatre), no having to show up several hours early, and the journey itself is pleasant while watching the world pass by outside. Delays are very infrequent. I've personally done some of my best thinking, coding, and writing while on a train.
There is, however, one major problem: trains in America are slow. Slow to the point that driving through Los Angeles (including traffic delays) is still about twice as fast as taking the Amtrak. There is probably some efficiency gain on longer trips, but who wants to sign up for a 72-hour train ride that could easily be a 36-hour drive or, more realistically, a two hour flight for the same cost?
I would welcome a revitalization of the rail industry in this country with open arms, but only if they do it right; after all, as a project that would likely be subsidized with tax dollars, I'd rather not pay for something that one one would use.