How?
> On the other hand, sharing information is easy.
Not in the way we are talking about.
> The hard part is in trusting that information in the time and age of spam
No, it's not. We're talking here about moderated Knowledge bases. Of course, if it's a poor or even unmoderated wiki, this would be a problem. But I've never got the impression that Arch-wiki had this problem.
> don't want to share too much by default for other reasons.
Sharing what? This is about open source? Is this AI-slope? O_o
> Also it is way easier just do something to your own wiki, than coordinate with dozens of others where you share something.
I don't think Arch-Wiki has only one maintainer.