I still think wikipedia hit those "this is my passion" sites harder than social media did. What's the point of building a site about widgets, when 90% of people are just going to hit the Widget page on wikipedia?
The point is to have a site that is not just going to be deleted because some permanently only jerk thinks Widgets aren't noteworthy enough.
Plus Wikipedia offers arguing about widgets with other widget enthusiasts/detractors as a first-class feature via the Talk page.
If you know so much about Widgets that you don't need to consult Wikipedia about them yourself, you know more than it'd accept anyway. Wikipedia does not compete with passion sites of people deeply into a topic; if anything, it uses them as citations.
Also, counting audience is a thing that matters when you're running ads, which kind of disqualifies you from the passion site category, or as a trustworthy source of knowledge.