Look, I'm obviously putting you on the spot ...so if ya'll need more time, as a mod group, to discuss it, fine...
But if it's a directive, please define how long between their last post and now is allowed before reviving a thread. A year? 6 months? A month? Just let me know.
And I get you're leaving it up to our individual judgments but isn't that the SAME judgments that are opening these threads now then others same judgements asking them to be shut down immediately? Asking us to define the nuances so you moderators have to make later judgments seems reductive.