Godot has had wikis in the past, they tend to die off since the official docs are already open for community edits. And it's hard to compete with that.
Same with Blender 3D, it used to heavily rely on it's wiki for documentation, but honestly very few in the community even edited the wiki, so when the readthedocs.org variant was set up for documentation specifically the wiki fell out of user documentation use very rapidly. Developers still have some use for wiki, but that's about it.
