When it comes to the economy and housing, I've heard it phrased as "Growth, affordability, preservation: pick two".
So, in contrast to your post, I believe what has really destroyed the character of many cities is not that they've grown or had lots of outsiders move in (that's been going on forever when it comes to cities), but that restrictive zoning has made housing so expensive that a diverse range of incomes can no longer afford to live there.
If anything, making it extremely difficult to tear down a dilapidated laundromat to build more housing because that laundromat has been deemed "historic" is what is changing the character of cities for the worst.
So, in contrast to your post, I believe what has really destroyed the character of many cities is not that they've grown or had lots of outsiders move in (that's been going on forever when it comes to cities), but that restrictive zoning has made housing so expensive that a diverse range of incomes can no longer afford to live there.
If anything, making it extremely difficult to tear down a dilapidated laundromat to build more housing because that laundromat has been deemed "historic" is what is changing the character of cities for the worst.