You’re looking at it from a coast to coast perspective when it should really be an intra-state one.
People aren’t regularly traveling from Chicago to La on a daily basis, even by plane. They are traveling within the same state or to nearby states instead.
Dallas-Houston, SF-LA, Miami-Orlando are all distances that people have to drive/fly to on a daily basis that could easily be replaced by hsr.
RPGs that aren’t dnd