But this was in the hypothetical of Wikipedia being sold or taken over. If people don't agree with the practices of the new owners and rally behind a fork trusted by the community, I expect most moderators and contributors to follow.
PR firms are really good at spinning and diffusing and confusing criticism. Not completely, but enough to split a community trying to rally behind anything that is against their interests.
The sale or takeover would start with promises that nothing would change, and then would change slowly enough that each editor would have a different breaking point and thus be too fragmented to move over at a specific point.
Of course there are network effects for moderators. One major reason people volunteer to moderate Wikipedia is because it's in such ubiquitous use.
A fork of Wikipedia with no community is just a content mirror and, because of network effects, you'll have an incredibly hard time attracting anyone to help out with it when they can just go to Wikipedia.
