I don't know if that's quite what's happening here. It's probably more that Wikipedia (and maybe a few other heavily Wikipedia-inspired, MediaWiki-based sites) is the only exposure most people will have to the wiki concept. The range of possibility didn't exist in their minds in the first place.

Fair enough.

It could be described as a sort of group bias. People would have been capable of seeing a range of possibility except that a strong example channels their minds.