What possibly was the logic here?

This is 100% correct. I’ll add that the best thing you can do is to watch and listen to your crew. Everyone has a job, yes, but they also play a role on your team. Understand what those roles are, how work actually flows around, and what motivates people. Be a servant that helps facilitate that structure.

I’m not sure how you feel about the limiting thing, but it is controversial in the US. Some departments do limit, others feel that isn’t fair. Personally, I think we should understand why the academia system is set up the way it is and ask if it makes sense in the modern world.

As a grad student mostly. That said, non-tenured professors also have to work their asses off. The pyramid scheme dream is becoming tenured and having a large pool of grad students to abuse help you with your work.