Would there be a way to make a new community that acts as a kind of graveyard for content from deleted communities?
XYZ times out and gets auto deleted; all of its threads move to the graveyard. Disallow new threads in that community except by transfer from a deleted community; but allow new comments within those so that they still have potential to generate content from folks who landed there from a search.
Clean up derelict communities without actually losing anything - win win.