They don't necessarily know what is marketing and what they are buying, and the few truly top schools are selective. Private school teachers are also paid less & have worse benefits. It would be great if the private system had it all figured out but they don't.

The low pay does somewhat select for teachers who want to teach - as those who don’t can get more money elsewhere.

The main advantage private schools have is they an expel problem students and let the public schools try to handle them.

> The low pay does somewhat select for teachers who want to teach - as those who don’t can get more money elsewhere.

It ends up selecting for people who are more transient and have less experience, who haven't gotten the better Public school job yet.

> The main advantage private schools have is they an expel problem students and let the public schools try to handle them.

They theoretically have more control over expulsions, but whether or not they use it really depends on the school.