A lot of wikipedia articles about STEM-related topics are way too technical. They might be factual, but if you don't already have a good understanding of the subject matter, you'll be confused. The people who write this stuff are smart, but they're not good at trying to make it palatable for beginners.
A good place that solves this problem is simple.wikipedia.org. It's written for people who are new to the English language, all in basic English. There are 139,284 articles as of when I'm posting this.
There are almost 6 million Wikipedia articles though, meaning many of them don't have simplified versions.
While you are correct that Simple Wikipedia is meant for people new to English, it is misleading to say that is a solution to too technical articles.
What would a solution to articles that are too technical?
I think the author has to make an effort to present the concepts clearly and w/o any fluff; something following George Orwell's writing style would lend itself nicely to re-writing a technical article.
But those articles aren't always the most enjoyable to read.
I would think there is no need to simplify them. If you don't know the topic it would be better to pick up some introductory level reading on it instead.
Shouldn't Wikipedia articles be introductory, since you probably don't know much about a topic if you're looking up an article about it?
I think Wikipedia articles should be introductory, yes, but in a big picture sort of way. They should state properties, what those properties do, how that changes interactions, and how all of that is utilized.