There are two goals accomplished by teachings university level students.
One is to educate the people who will, in a few years, be professors in academia, or entrepreneurs in innovative businesses, or CEOs of large companies whose decisions have significant impact on society. The idea of shaping the knowledge of tomorrow's leaders was very present when I taught at Ecole Polytechnique in France.
The other one is to educate people in general, forming the minds of our the new adult citizens who will be voting and holding jobs everywhere in society. That idea was very present when I taught at Universite Paris-Sud in France.
For the first goal, the focus of attention are the best students in the class. The instructor tries to constantly challenge them, stretching their mental agility and pushing them to learn as much, as deeply, and as fast as possible. The students who are in difficulty are not on the radar. For the second goal, the focus of attention is the majority. The instructor tries to reach as many students as possible and is focused on the fringe students who are struggling to learn the course material. The students who are effortlessly cruising through the course are mostly ignored and are sometimes even considered to have an unfair advantage. So, to some extent the two goals are in tension.
It's one of the difficulties of teaching at a large public university. For example, if you teach a class of 100 undergraduates at UC Berkeley: are you going to spend effort on the two or three students who are shining in class and who might, with encouragement, continue on to a PhD, or on the thirty students who seem to have overreached slightly by taking the course?
At a selective institution such as Ecole Polytechnique or Stanford, the problem is largely solved by the filtering that happens beforehand.
Teaching with both goals in mind is taken to its limit this semester Stanford, with an online course being taught on introduction to AI. The course material is taught to the Stanford students, a selective group if there ever was one, but also, in an online manner (including automatic online grading of homeworks and exams), to the entire world, with no filtering whatsoever. How can that be?
There must some self-selection, so that the unknown crowd of students taking the course online are each, individually, a student who is highly motivated, smart, hard-working, and who, in different circumstances, might have ended up in Stanford anyway. It's an idea very much aligned with the American Dream: offering an opportunity for all to better their education, regardless of social class or circumstances of birth. That makes the project an idealistic and, if even half-way successful, exciting endeavor.