I too know that of which you speak. The town I grew up in rapidly suburbanized, going from 5,000 people to 35,000 in 10 years. 100% of the farms were lost. The town eventually settled out at about 45,000 people. I can recall going back to my 20th high school reunion. Where I lived was the old part of town where multi-generational blue collar families lived in stark contrast to the upper middle class subdivision neighborhoods in the rest of the town. Though we were but a small segment of the high school population, the kids from my neighborhood that I started kindergarten with and eventually graduated with were probably half the attendees. We had roots. The newcomers didn’t and when their Dad got transferred away or retired to somewhere else they had no ties to the community to bring them back. All of my grandparents, aunts, uncles, & cousins lived in my neighborhood, and the rest knew my parents so there was no getting away with anything growing up there.
Despite the slowly falling (and aging) population I love where I live now in VT in part because so many here have deep roots to serve to preserve the culture, and with no development pressure the landscape gets preserved too.
That upscale suburban county where my daughter lives is picture perfect in every conventional way but it is sterile. There is no sense of history. Its all been bulldozed away. There is not a unique personality that an old community has. I understand the draw for young families. They just don’t know what they are missing is all.