I'm scoutmaster for my son's troop and this is one of the foundations for the BSA Patrol Method.(It's also talked about in lots of other leadership trainings) Once you move out of 6-8 in a group things break down quickly.

You also hinted at servant leadership. As a leader my goal to make sure the folks in the group have what they need to get the job done.

There are still management details, plans, schedules, budgets and what not. But, that's a separate thing from leadership.