Schools to stay top-tier have to keep a critical mass of students who could move elsewhere or go to private schools. If those students or their parents feel marginalized by a broader spectrum of students, they'll leave in droves. I've seen it happen.
Also, keep in mind that the less qualified quota students are replacing student who are more qualified. That in itself lowers the standards.
“Also, keep in mind that the less qualified quota students are replacing student who are more qualified. That in itself lowers the standards.”
Amazing how that happens, and in 3-4 years, the standards are really lowered.