The point is not whether we would want to live in Japan or Eastern Europe or whatnot, the point is whether rail travel makes sense, and there can be places where bullet trains or fast train service make sense. There are heavily travelled corridors, like Boston-DC, San Francisco-LA-San Diego, places that have heavy car traffic on the roads and where plane travel is congested, where having fast trains might make sense. Japan has bullet trains because they are densely populated and it made sense. Trains generally make sense in densely packed areas where there is a need for multiple forms of transit,for example densely travelled roads and airports. Some longer runs might make sense, like Chicago to NYC, if the train speed was such that if you add up the time of flying, getting to the airport, security and so forth, might be worth it.
In terms of the cost, it would have to be looked at in a variety of ways. If trains for example can take some of the burden off of airports and the skies over densely packed corridors, the cost might be offset by the savings in not having to upgrade air traffic control or expand airports, not to mention costs of overcrowded airports,the cost of delayed and cancelled flights, and so forth. Likewise, if trains take some cars off the roads, the cost of the trains should be offset by savings on repairing roads, on not having to expand them, fuel saved, the cost of traffic jams averted and so forth.
