The story often goes that someone destroyed a fully operational system for profits when in fact the system was badly deteriorated and not really used a lot.
I'm not especially pro-suburbia--I live in an exurban/almost rural location. But I think it's perfectly understandable why many people wouldn't live in a city given a choice which they increasing had post-WWII in the US.
Seems like you'd be S.O.L. unless the government kindly free-markets a continent-wide network of paved roads, with conveniently placed roadside stops along the way where they sell gasoline. Can't imagine why they would undertake such an exorbitant public works project when the transcontinental railroad already exists; it's not like the government is disproportionately influenced by any industries that would very obviously materially benefit from such a thing.
Popular explanation but largely false. They were destroyed because people quit using them.