I did my PhD in a group with ~20 students and postdocs including many co-supervised with some other department. The prof in charge of the group had his name on > 90% of the papers we published, I believe justifiably. He would have read all of them, and written sections where appropriate, and had a hand in directing and organizing the research as well as challenging the results and strengthening the presentation of th…
I'm glad you felt comfortable with that situation, but not all are like that. Sometimes the involvement is very nominal and unnecessary and there can be unintentional side effects that aren't always obvious, in a form of "attribution manipulation." I can think of situations where a researcher is basically "joining" projects whenever possible to attach their name to it in a form of branding. When a junior person comes…
I challenged the thing one time to an intermediate supervisor (who where at least really contributing a bit) and I got bullshit excuses like "he's securing funding", "running the lab"... well at least not for my project since it costed nothing and I came with my own funding. At this point the toilet cleaning lady was contributing more to the paper because of how she allowed me to work in a clean environment.
So I'm not surprised by Japan being over-represented like mentioned in the article. My lab explicit policy was "quantity over quality" written in a presentation given to new student. I know have a mental, logarithmic curve of contributions from authors: first made 90% of the work, second 9% and the following authors share the last 1%.