Perhaps of interest to participants in this discussion: https://en.wikipedia.org/wiki/Wikipedia:Wikipedia_Signpost/2020-03-01/Opinio..., titled "Wikipedia is another country", by User:Gog the Mild (https://en.wikipedia.org/wiki/User:Gog_the_Mild).
I'll quote two paragraph of this essay here. (For the license for this text, see https://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution....)
"Which brings me back to psychological preparedness. I was not accustomed to being the new member of an established group and the slow kid at the back of the class at the same time. Relying on the charity of others to metaphorically tie my shoelaces. It grated. This was entirely my own, fairly reasonable (I think), issue. Nor was I prepared for the casual offhandedness which is fairly common. Recently I suffered a mass revert with the edit summary "Learn some intellectual property law". This bluntness rankled. It was my issue rather than the reverting editor's, but that didn't help reduce the rankle. Since discovering MilHist I have stumbled around in this small corner of Wikipedia, occasionally bumping into helpful tools which I endeavour to clutch close.
"The near complete lack of usable guides – IMO – to the basics is heavily compensated by the, usually, enormous willingness of complete strangers to spend time and effort correcting my idiocies, reducing my ignorance and remembering that they too were newbies once. Members of the Military History Project have collegially made the project a comfortable place to work in such a natural, even graceful, way that what they have achieved seems normal."
My guess is that many good novice users quit after encountering interpersonal, procedural, or technical problems which they don't know how to resolve, or exceed their tolerances. I think that English Wikipedia's Teahouse has been successful with addressing some of these issues, but as Gog the Mild notes, we could do more.