“But the joe6p family of five I just described isn’t helping their surrounding values”

That’s it, it is not their problem to help surrounding values. I don’t have any such responsibility either unless I live in an HOA. I lived in Normal Heights and owned two houses there, both purchased as fixers. The people who couldn’t fix their houses up, and there were plenty, never had anything but sympathy from me as long as they were nice people, which very many of them were. Mine were always very tidy, but that did not change my views. I always figured that they were doing the best they could.

If people didn’t let their houses go down hill what would fixer flippers buy? Or fixer rental owners? It all works together.