The main thing a good manager can do is act as a wall between the engineers and everyone above them, which is hard to do politically because it exposes a whole subtree of the org chart as useless.
I think that's a little myopic because that subtree is providing the comfortable fiction that you can just go into work, do engineering, go home, and get a paycheck. I'm not saying I don't want to blow my brains out dealing with them but it's comparably a small amount of pain in return from being completely insulated from all of the realities of operating a business and the messiness that entails.
