In other words, existence proofs that such systems won't automatically be ruined.

I'd disagree, they require a massive amount of moderation and clean up to keep running. The default state is ruined and only by herculean effort is it usable by others.

It's like a park in a high drug use area. Quite often they are ruined, and only by massive expenditure of effort are is it even near safe.

Even if your reply made sense as a response (it doesn't), I've been involved with multiple wikis, and your claims aren't true.