Open access journals are not going anywhere soon and hypothetical reliance on them would be a death sentence to Wikipedia because their range of coverage is so narrow.
As for JSTOR, tens of millions of Wiki users get immediate full access as do patrons of 6500 libraries and practically all students in higher education in US, UK, Canada, etc.- They have access but do not use it when they edit for Wikipedia--I suggest they do not know about it. (about half the Wikipedia editors are younger than 23, suggesting that they are probably students with free access to library services.)
As for scholarly articles, a common format is for the first part of the article to summarize the state of the art and the remainder of the article to present the author's original research. That first part is especially valuable for Wiki editors. ~~~~