Suburbs were invented with one goal: survive and win an all-out nuclear war, getting an edge over Commies which they could neither economically nor ideologically afford to replicate.
Commies are long gone, that goal no longer applies, move on.
But suburbanisation properly became a thing with policies of destroying public transport, and redlining that while invented in 1934, started to get massively applied around 1947. Destruction of public transport made living in inner cities more difficult and in suburbs, relatively easier - and redlining made people feel compelled to move out out inner cities.
Commies are long gone, that goal no longer applies, move on.