> WeirdGloop also runs wikis for the biggest, most active games and communities in the world

Most of the costs are those that scale up/down by activity - MediaWiki itself is free/open-source and the wiki's content is contributed for free by volunteers.

Also, keep in mind I'm not saying that each wiki needs to be individually self-hosted. Can be a host the size of WeirdGloop but made up of smaller game wikis, for instance.

> I'm more concerned about the rest of the wikis like the example I gave where I'm googling for game mechanics for a dead game.

Prospects for long term information accessibility are pretty terrible on sites aggressively squeezing out all the profit they can. See Reddit eliminating archives and third party clients and then cutting off all search engines that don't pay, or mass deletions of user content by sites like Photobucket/Imgur/etc.

> You can migrate wikis away from Fandom. The OP is about doing just that.

With significant difficulty, fighting against both Fandom's policies and SEO/network effects. The OP lists "wiki communities need to be able to freely leave their host" as the primary rule for "How to not turn into Fandom 2.0".

> You have to stick around for another decade so people can find that information long after you've lost interest

Hence ability and willingness to pass on the torch is critical - so that the information doesn't die with one person or company.