Interstate Highway Exits. There have been efforts in recent decades to try to reverse this, but it will take many many more decades (and some previously non-existent or poorly trained City Planners) to make it happen.

pronounced in plenty of areas which all look the same from coast to coast. I've read that malls, the commercial 'community center' in many areas are dying likely due to the growth of online retail, lack of funds and consciousness. Mega churches also became the local center for residents in some suburban and exurban areas for decades.

Newer sprawling suburbs that lack trees and walking spaces are very unhealthy for humans and the environment. I tried it briefly for more home space but couldn't adjust to the change after growing up and living in city neighborhoods.