Top athletes generally make lousy coaches. What they are trying to teach others to do comes so naturally to them they can’t explain how to learn to do it.
I suspect something similar applies to music.
i disagree... i have had coaches who did not get as far as their students... could not do the things their students eventually accomplished, and they were good coaches... and come on, the Suzuki method has been around a long time... my sons have had a wonderful piano teacher who has taken them further than she has gone personally...