Technically a large landmass, but essentially nothing happens in the western half. For the sake of travel it is a relatively small country. Whereas NY->LA is the route the USA would need to most service if it were to get serious about such a thing. The short-run corridors are already reasonably well serviced.
Trouble is most people doing the NY->LA run are going to choose flight instead.
Trouble is most people doing the NY->LA run are going to choose flight instead.