> You're delighted at the students that have passed your IQ test. There is generally very little care given to the 70%+ of students that aren't making the cut.

That's because happy students are all alike, but every unhappy student is unhappy in their own way. It's just not feasible to care in depth about why any one of the 70%+ is not learning effectively. They're probably missing something that's effectively a prereq for the class, but that's something that should be addressed by the student themselves.