There is an unwritten rule that that older stories are treated more leniently under quality standards and should only be hit with an M4R if you have a really good reason. Helel had to warn JDeschene a few months ago because she M4R'd a bunch of stories from years ago without being aware of this custom. As Helel told her, if the story has been edited by a staff member, especially recently, it's probably good to stay.
That said older stories are not immune to M4R, and I actually marked a five-year old pasta for deletion a couple months ago because I knew there was no way staff would not want it deleted once they saw it.
A few months ago Empy also M4R-d an old pasta that had in the past been edited by staff because it was a basic undeveloped narrative of a sex offender mentally fantasizing about raping his next victim as she exited her school without there really being anything else to it, and he recognized that the community had changed enough since 2013 when it was posted that it was time to revisit whether it belonged on the wiki even with it being posted before contemporary quality standards. The admin who reviewed it agreed and deleted the page.