The US is physically big enough that coast to coast would probably always be a fairly niche pursuit. New York to SF, say, is about 4700km. At 300km/h, assuming no stops, that is 15 hours. Most people won't want to do that.
Seattle to SF, however, is only about 1300km, so a bit over 4 hours under ideal conditions. At that point, it's probably quicker than a plane (no need for the whole getting to and from the airport thing, or the security, or the inevitable delays).
Seattle to SF, however, is only about 1300km, so a bit over 4 hours under ideal conditions. At that point, it's probably quicker than a plane (no need for the whole getting to and from the airport thing, or the security, or the inevitable delays).