Suppose that there are 1% of people in a field who are considered great at doing and 2% who are great at teaching, then just from expectation without additional

Suppose that there are 1% of people in a field who are considered great at doing and 2% who are great at teaching, then just from expectation without additional knowledge the vast majority of great teachers won't be great at doing. Also, if the percentage of people who are great at both is higher than 0.02% but lower than 1%, there is a positive correlation between teaching and doing, but it is not a perfect correlation. I suspect this is the case. Why? Both doing and teaching something well often require clear and systematic thinking. However, there are also disparate skills required for each and only those with time, inclinations, and opportunities to practice both skill sets could become great at both.