I’ve seen plenty of communities where it’s clear that the mods only stop by from time to time and they get by just fine, spam and malicious posts will still be a small minority. Some set automod on a shoot first, ask questions later setting where all reported comments get deleted until the mod restores them.

I really don’t think finding new moderation will be an issue. As much as it would be nice for Reddit to be screwed over by the mods it’s going to be a non-issue for them, there’s already measures in place to prevent subreddit parking and plenty of willing volunteers.