> So the developers take on the responsibility of a manager so they don't need a manager? The value of a good manager is that they can do some of the stuff on that list so the developers don't have to (ideally including all the 'fighting').

Incompetent managers fail to unblock their teams and instead push pressure on their reports to "fight". Often blocking career growth, promos, compensation changes with these reasons.

I'm sorry. If the dev ultimately does this work, the manager should be fired or made an IC where they can demonstrate their value.