Fandom hosts a lot of wikis for long forgotten nich'e games and with these games there usually isn't enough interest to move to another wiki. When it comes to these wikis theres rarely if ever a team behind updating the wiki and more often than not the content is just being updated and maintained by random invidividuals who just happen to be engaging with the content at given time. The very low barrier of entry makes this possible as you don't really need to join a team to edit pages or even coordinate with other people.
When playing one of these games I like to record and share some my observations and findings about games mechanics etc but more often than not the only wiki I can find is fandom wiki that is either incomplete and possibly even abandoned. I cant be bothered to create my own Wiki for these games so I'll just start editing that one instead because it's easy, the foundation is usually already there and I don't need to bother taking any sort of responsibility/mantle of maintainer or admin.
While Fandom may not be the most optimal choice and there may be better ways to host wiki out there its still better than some obnoxious google document or poorly formatted steam guide that no one else can edit.
What games are so small as to not be capable of generating a non fandom wiki, but are large enough that the wiki is not completely empty and factually incorrect?
The problem is that the content is already in wiki fandom and there are no contributors invested/interested enough to migrate all the information to alternative wiki. These fandom wikis have no teams just random individuals making contributions of various sizes.
If I do ever get invested enough to a game to actually create a wiki I'll definately use something else than fandom.