[roel_v]

I agree, I think many people would pay more for their children to be taught by a teacher who has demonstrated superior results. Which is different from paying for private schools, because as a parent you still aren't sure by whom your children will be taught.

Additionally, there is the political issue that proponents of more egalitarian and redistributive systems will claim that this would be disadvantageous for those who can't afford expensive educations. Those children would be left with the bad teachers, reinforcing their lower social position. I presume we won't find out anywhere in the lifetime of anyone reading this now.