>They couldn't wrap their heads around the concept of casual crowdsourcing.

I'm sure they could, most teachers aren't idiots. And they were correct that "casual crowdsourcing" is not a fitting replacement for peer review.

And in fact, the current moderation policies for Wikipedia only work in so far as they use peer-review type processes, such as requiring "notability" and multiple sources, and preferring expertise in a field. Of course, if you're in a relevant field you shouldn't use Wikipedia as a primary source since you would presumably have access to whatever sources the wiki itself cites in the articles.

If I were to make Wikipedia once again from the ground up I would put more attention into building reputation system of contributors. If you have more reputation you are allowed to edit something and/or your edit has more weight.