1 Wikipedia has no ads (besides the occasional ones fundraising Wikipedia itself), loads fast, is information dense ― has an excellent user interface with clear menus and clean formatting. People default to it increasingly because a good portion of everything else on the first page of google (switch to searx) is increasingly lacking these traits. Unfortunately this has led to many ― notably journalists under large networks ― to make edits to Wikipedia pages specifically to cite their own articles to get more exposure.
2 In their credit they (the Wikipedia people) has made an effort to remove external incentives for editors to make edits ― notably by making all the links from their pages ‘no-follow’. Normally a search engine like google ranks pages higher if they are linked by other pages that get a lot of views ― websites that linked from popular Wikipedia pages would normally be boosted hugely by the algorithm(s) ― but by making a link ‘no-follow’ Wikipedia is telling google (and other search engines) not to rank the pages that it links to any higher regardless of the fame the Wikipedia page is getting. The thought was that because the links are no-follow and don't give any algorithmic advantage that people would not go out of their way to get their articles linked on the pages.
3 Coding a link as ‘no-follow’ doesn't solve the issue of professors telling their students that it is "acceptable to use Wikipedia for general understanding as long as you take a look at the links at the bottom for reference". Or of the rest of the web being unusable leading people to default to Wikipedia. Large parts of the site still have an extensive ‘systematic biases’ towards groups wanting publicity further negating any miracle of aggregation that supposedly exists.
5 External motives to edit pages like the chance for external publicity adds even more distortion to the project. Don't think that Wikipedia pages or the sites that they link have been created and linked together ‘organically‘. If something can be gamified then it is likely that it already is.
