The answer is simple, but "we" can't handle it's implications.
Separate students by IQ, and tailor the curiculum and pace of learning accordingly. It always works for the benefit of the greatest number of students. And for the society at large.
But...
There will be very, very few "disadvantaged minorities" in the top classifications. There will be no "special needs" kids in the top classifications. Indeed those students will populate the lowest classes.
Leftists, who control academe, have this silly and counterproductive view that if the system works properly, everyone will end up being equally educated.
Stupidity on steroids. We know what must be done, but lack the courage to do it.
Fuck us all.