https://ieeexplore.ieee.org/document/5089308, from RCIS 2009 (Beel and Gipp) noted that "Google Scholar seems to be more suitable for searching standard literature than for gems or articles by authors advancing a view different from the mainstream."
Unrelated, but interesting: scraping Google Scholar is remarkably annoying if you want to actually use the data. The easiest way (in my experience) seems to be regex hacking on the BibTeX files, but this seems truly broken.
Google has basically got as bad as twitter in terms of giving a big middle finger to third party devs, but they have been smart enough to maintain a completely useless public/free tier for most things.
A piece on how a researcher spent a summer filling out CAPTCHAs / scraping: https://www.nature.com/articles/d41586-018-04190-5
Given the high attrition rate in many academic fields (and the small number of publications typical in early years) this would then rationalize the low numbers seen here. Though, I would say the meaning of these numbers would be quite different than if this were presented for those who had research careers (the more relevant number I think).
It's a very very small overall percentage of authors that publish more than one paper per year!
My father, born in the 50s and like another commenter discussed primarily involved in industry, appears to have three or four.
Back to the article, lots of gems, like:
>Today's researchers can publish not only in an ever-growing number of traditional venues, such as conferences and journals, but also in electronic preprint repositories and in mega-journals that offer rapid publication times.
Did I just read a very normal point of view of a researcher putting on equal footing electronic preprint repositories and mega-journals?
The BOAI Open Access preachers surely can't believe their eyes :) Heresy! (No researcher was involved in the BOAI flawed definition of green OA as archiving and gold OA as publishing.)
> Overwhelmed by the volume of submissions, editors at these journals may choose safety over risk and select papers written by only well-known, experienced researchers.
There is a bit of a "circle jerk" in this process: if you know the right people, you can get better reviews. In return, you review their papers or requests favorably. That also leads to repeating authors.
Academia is literally all these people know, and they've been sheltered their entire lives. No one should be surprised that this produces strange results.
Obviously there are exceptions, but there's no denying it produces some interesting world views.