[trip42]

The US education system benefited for a long period where many incredibly smart women had career options basically limited to teaching and nursing. As equality improved, some of the brightest prospective teachers instead became doctors, scientists, and engineers. This decrease in teacher quality is resulting in a more "assembly line" style of education, where each step is fully structured. I have seen anecdotal evidence of highly qualified teachers exiting the workforce because the structure of the work has become unfulfilling.

I suspect there are also incentives for top performers to move out of education and into administration.