MediaWiki is pretty technically challenging to self-host. It updates frequently and the updates are nontrivial to do especially if you have a large userbase. Also, if you want an extension like Cargo, SMW, DPL, etc, that lets you query data from one page to another, your server demands will go up a lot and hosting can get quite expensive.

There's a new competitor though for gaming wikis that's started hosting some forks & some new original wikis, https://wiki.gg/.

Disclaimer: I was a contractor for Fandom until they terminated me in August this year (I ran their esports wikis including Leaguepedia).