Private groups have very little value with the new rule system. The reason they thrived in the beginning was because they provided a place for people to set their own rules. That's not really necessary anymore. They could still be quite popular for long standing communities of tight members, and from what I've seen, they are. But newer groups are certainly going to have a more difficult time convincing people it's worth the effort. No doubt some groups are dying. And I don't personally like that either. But the lack of moderation tools are not the cause of it.