“As an educator myself, I am happy to grant that teachers produce value for students, and for society. But even the most marginal teacher, at the worst and least motivated public school, can’t-wait-for-retirement clock puncher, makes far more than the marginal basketball player. You can’t compare the marginal unit of water, or teachers, with diamonds.”…

I actually don't think this is a great comparison. Both basketball and education are heavily distorted. Basketball by the monopoly of the association and teaching by public sector funding and unions.

I'd argue you can't really compare marginal anythings in either basketball OR teaching