I've watched quite a few Hoarders shows. There were a few that did lose their houses, either because it was so decrepit once it was cleaned out that it was unliveable, or because it wasn't worth the money to fix it up. On one episode, the new buyers helped the woman clean it up, fixed it for her and either sold it or rented it back to her (I forget which). That's an amazing thing to do.
All of the people are offered aftercare to deal with the issues that got them there in the first place, but some don't follow up. There's a fair number who backslide into old ways even with therapy. It's interesting that for the people that do succeed, their entire manner changes - they present as much more normal in terms of attention span, communication abilities, etc.
The common denominator in the hoarders is some sort of loss (divorce, death) that triggered the behaviour, although some had been that way since childhood. I find the show fascinating.