If you can't log in or transfer the house over (like in an FC's case) in the time frame they offered (or any time frame that's reasonable) then why bother to own it? You should obviously lose the house to free up houses for people who actually do play.
Yeah, but freeing up space wouldn't be an issue if space wasn't limited. I played Lotro man, and having that house payment tie us down and eventually have us lose the house we loved and decorated wasn't a fun time. People spent a ton of time getting enough money to get those houses, losing them would blow for those dudes. It's better for everyone if they open up additional space rather than have people lose the houses they cared about when they played.