This is completely fair and is absolutely a very real thing for many people. But only about 19% of the US population lives in rural areas, for some definition [1] of rural.

Unlike rural areas, cities are dense enough that we could certainly choose to build them in a different way, so that we are not all completely dependent on our cars to go anywhere. For a lot of folks, I think it's definitely a discussion worth having.

[1] https://www.census.gov/newsroom/press-releases/2016/cb16-210...