This debate occurred throughout the 60s and into 70s. They let them in, and they did the same as everyone else. Wining 15% of basketball championships while being 11% of the schools.
Then came open enrollment in 1988. This gave public schools an advantage. Free education drawing from wherever they could.
Things didn’t change through the 90s. That is Until they did At the turn of the century, private schools started dominating.
Instead of leveling the playing field; How about public schools, figure out what private schools have been doing to kick the shit out public schools for so long? The same happens in academics too.
The answer is: the private schools do the same they always have done.
My theory, is public schools policy became hyper political. Driven by guys like Bill Ayers. You can hear it him constantly echoed in politics too. They worked to dumb down schools to make everything level.
The privates continue relying on rigor, self discipline, and other empirical successful principles they have employed since John De La Salle started his first La Sallian Brothers schools for the poor, in the 1680s.