If the mods had a collective stroke or other cerebral failure and started locking threads because they were "too long" I, for one, would wander off elsewhere. There are barren technical sites where discussions are limited to one question and a few posts to answer it, then locked. This isn't one of them.
And for the love of Mike, what do you call an "ancient" thread? Looking at the currently active topics (courtesy of "Today's Threads") and leaving out the Politics & Religion forum and the Lounge, which are off-topic and meandering by definition, out of the first 20 threads, the oldest is a promo for a book in Author Self-Promo going back to last August (it seems to have spawned quite a discussion) and there's also a calibre technical thread (an archive of download recipes) going back to October, but all the others are from this current month. Yeah, no thread older than three weeks. In fact, only four topics are older than a week (that is, between 1 and 3 weeks).
So it appears that you're calling threads less than a week old "ancient".
Less than a week old.
I think there's a problem here indeed, but that problem is not the unwillingness of the mods to lock threads when you get tired of them.