The difference is decades of economic policy that encouraged people to dump their life savings into owning their own home. When you've invested heavily in something, you tend to suffer from sunk costs fallacy. Add to that the fact, that those that own the homes and the land are typically the leaders in their community and you have those invested in a place encouraging others to stay there as it dies. Those that own the home can move out, but if enough do so, then the only prospect for the laggards is abandoning the home and losing it all.

I agree that people should move, but circumstances are different today.

I'd love to see more sociology and economic research in how towns die and recover. Tons of money studies urban poverty and decay, and I suspect rural poverty and decay doesn't get nearly the same attention because it's out of sight and out of mind for those funding the research.