That’s the definition of a good coach.
There’s a difference from being a great teacher and someone who knows the game inside and out.
You can be a great strategist. A great analytics guy, etc… but being a great coach is a different skill. How good are you at teaching someone how to do what you expect them to do? That’s THE measure of a coach.
For instance, I believe Grimes is a great coach. I say that because wherever he goes you see improved OL play.