You not going to break the loop till you pay dramatically more to teachers, poor pay usually attracts under motivated people in smaller numbers, so you cant be picky. These people eventually get promoted, an you end up with poor quality managers running the school who take advantage of good teachers.

Its so self defeating as high quality teaching as you do results in better engaged students with better results that lead to life long improvement to the entire economy. Instead we have ladder pulling from the rich who want to kneecap state funded schools while enriching their own private schools to create a barrier for the majority to compete.