It isnt like the rest of the world doesnt have rural areas, unless one lives in like singapore or something. Something like 80% of the US population lives in urban areas, and most trips arent trips between cities except perhaps for those that are close to one another anyways. So even if one accepts that rural areas are car centric by nature, that still leaves the vast majority of the population that isnt affected by that. The buildings within cities being spread out over a wide space making transit less efficient is a failure of city design rather than something fundamental and unchangeable about the US, we have a fairly serious housing shortage anyways, if we really wanted to decrease car dependence we could absolutely build up denser housing in urban cores to shift the population over time into areas that allow for more efficient transportation.