The hard part about sharing is the different syntax of wikis, which could be slightly different even in the same wiki-software. Then there is the organization-part, and the sync-process itself.

Of course, today, 25 years later, we do have better solutions and much more experience for those problems.

> The maintaining is hard when there isn't clear ownership. How do the teams divide maintenance duties? How are vandalism and moderation dealt with across teams?

I would think those are pretty simply, as they all follow the same rules. I mean, handling vandalism isn't much different between Arch or Debian, it's always the same. And moderation really depends on the chosen sharing-mechanism. Which brings up again the hard part, just on a different level.