When you invent a story like this you can use it to "prove" anything you want. Alternative ending: the smartest kids rally around those failing and hold after-school sessions to bring their grades up. In fact these group discussions help improve the understanding of the material for everyone, even those already doing well. The grades go through the roof, and at the end of the class the students climb on their desks f…
I saw the class was rough for a lot of these kids, started a large study group and taught them, and the class ended up with 10 A's, one of them being from outside the group.