Reddit is banking on the mods coming back and re-opening the subreddit to avoid being ousted. Mods who have put their heart and soul into a sub for years won't want to give it up so easily.
I'm not so sure. My completely anecdotal experience across communities on many platforms is that users love to say "I'm gonna quit!", then never do it, but when mods say that they mean it. I can't recall any times I've seen a mod come back, but plenty of times where it's led to cascading resignations (if it wasn't a coordinated "mic drop" in the first place)
The currency of good moderation is respect, and if you tell a mod you don't need them, there's a high chance of them calling your bluff