Pan – you are missing the point. Duke itself says that more than 50% of the apps it gets receive the highest possible score based on Duke’s own admissions process for scoring a HS transcript. They don’t admit gobs of kids who meet Duke’s academic standards at the highest possible level. That’s completely consistent with turning down two thirds of the valedictorians who apply.
Also, with the advent of weighted grading, the days of the valedictorian who aced all their home ec classes is long gone.