I will say that is a gross oversimplification. However, as you can see, most of these courses are either taught by Assistant/Associate professors or professors who aren’t involved too heavily with research. One such example is Machine Learning 289A at UC Berkeley (a fairly popular course). Its taught by two professors during Spring and two Associate/Assistant professors during Fall (https://www2.eecs.berkeley.edu/Courses/CS289A/). Graduate Students are usually the Teaching Assistants (TAs). In fact, some courses at both universities even hire undergrad students as Teaching Assistants.