That seems quite bad. It's a graphic example of how when it comes to public schools, or public policy in general, things get dumbed down to the lowest common denominator in the interest of "fairness" regardless of how unfair it is for those who are ready and able to do more. I don't know how that would get fixed, other than, as you said, moving to private. When you are paying directly (versus indirectly via taxation) you can demand a lot more.