For instance, a topic from April 2011 on “ontologies and semantic web” just re-materialized in the off-topic discussion section, even though it never received any response to its single posting “way back then.” I can therefore see no technical justification at all for it popping-up now.
Also, I categorically recommend that topics beyond a certain (fairly short …) age should be automatically locked. Blender changes very rapidly, so old topics are often no longer relevant, and it is very confusing when such a topic re-materializes. One might not immediately realize that a previous comment or the first one was from a previous decade. If someone wants to “add to the discussion,” let them create a new topic which (perhaps) contains a hyperlink to the old one.