The article explicitly covers this question. Looks like they're setting up explicit legal(?) agreements. One key point is the domain name: minecraft.wiki, for example, not a subdomain of something owned by Weird Gloop. So the wiki can leave if it wants to.
Does that mean that to the users of these wikis, the switching costs[1] of the backend would basically be zero (one day they might just end up on a different server with the same content), while on the administrators' side the switching costs are at a reasonable minimum?
[1] a variable in whether something can be enshittified, via https://en.wikipedia.org/wiki/Enshittification#History_and_d...