Are you saying peer-reviewed conference papers make something "notable" for mentioning in Wikipedia (next to historic and outdated 20 yo material on the subject)? That's not been my experience at all; what is or isn't notable seems completely arbitrary to me.
Yes, if you can find a subject mentioned (by third parties, not just people discussing their own project) in multiple peer-reviewed papers, that is better for establishing notability than blog posts, arxiv preprints, github repositories, pages in SEO content farms, web forum comments, or first-party white papers or press releases.
The criteria are that the coverage is “significant” (i.e. more than just a throwaway mention) and made in “reliable sources” that are independent of the subject of the article. This certainly includes peer-reviewed papers. For examples of reliable sources, see https://en.wikipedia.org/wiki/WP:SOURCETYPES
I don’t understand what you are getting at with “... next to historic and outdated 20 yo material...”
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Once notability for the main topic has been established, the criteria for validating specific claims is a bit looser. For example a company’s own website could be used to demonstrate the current version number of a piece of software, a press release (or even a tweet) could be quoted to describe the company’s first-party response to some event, an arxiv preprint from a tenured scientist or mathematician could be used to support some mathematical formula, a blog post by a living person could be used to validate their birthday or the name of their spouse, and the like.
most academic peer review is at this point is a joke though. i know everyone wants to hold onto it as some kind of high standard but it really isn't all what it used to be, it functions almost identical to SEO for academics at this point.
this dated mentality combined with wikipedia's culture of inconsistent topical gatekeeping is the source of much strife.
If you take a reductive point of view, everything in life – school applications, job interviews, business deals, legal battles, courtship, .... – involves some amount of self promotion and every form of social proof can be gamed/hacked to some degree.
(For example, in 2005 Google made up a brand new prize to award to Ruby on Rails creator David Heinemeier Hansson expressly for the purpose of padding out his O-1 visa application to move to the USA. Does that mean the O-1 visa requirements/criteria are bullshit? Maybe.)
(a) Wikipedia notability guidelines can certainly be gamed to some extent by motivated self-promoters who are willing to jump through hoops to place their pet topics in newspaper articles, research papers, published books, etc.
(b) Sometimes Wikipedia ends up rejecting topics that should be included based on a lack of sufficient third-party write-ups in secondary sources.
But Wikipedia still has to have some kind of guideline to prevent itself from being flooded with self-promotion spam, and the current notability guidelines and reliable source guidelines work better than many suggested alternatives.
