At a major research University, you’ll see the same type of thing a lot of the time. I was a science major so the professors usually taught the classes, but the T.A.'s (teaching assistants–who are usually grad students with more than five years of college under their belts and who are working on their master or doctorate degrees) ran most of the laboratory classes while the professors made rounds to ensure that everything was good to go.
As a University student, you are given the privilege/opportunity of watching experts work. In my case, I was able to look over the shoulders of world renown scientists, some of whom had invented new medicines or made groundbreaking discoveries. These folks had the job of GUIDING and INSPIRING us by showing us what and how to study, and by clarifying stuff during lectures; however, most of the learning takes place outside of the classroom–reading your textbook, practicing what you’ve learned, applying and thinking about the theories, coming up with new ideas, etc…
A professor (or Sifu) is only one person. They need to rely on their T.A.'s (or advanced students) to do a lot of the teaching. These higher students should be more than qualified to teach the newbies the basics, whether these basics are Wing Chun or scientific ones. Of course the professor/sifu will often instruct the class or at least check on things to make corrections/suggestions, however, their valuable time is often better spent helping the higher level students and/or working on their projects which will further add to the knowledge base which affects the whole discipline. I frequently felt honored to even be in the same room with some of my college professors, even though I was paying tuition to be there. I learned the basics (i.e. scientifc method) just fine from the T.A.'s who were very knowledgeable and handpicked by my professors.
At my Wing Chun school, the Sifu is often in his office talking to prospective students or doing whatever. I look at this as an important thing for him to do. Afterall, I’d rather learn some of the basics from my Sihings (who are very skilled) while Sifu takes care of business, than have the school close because we couldn’t pay for the rent and other expenses of our kwoon. If Sifu was out playing golf, and if my Sihings didn’t know what they were doing, then it would be a different story of course; but as it stands now, the students who put in the concerted effort and time into learning at my school are doing just fine.
Everyone has a different situation, obviously, so you should trust your instincts on whether or not you’re being “cheated” out of an education. However, a student-teacher relationship in a martial arts school or a university always has and always will rely on teaching assistants. Learning is a different endeavor than paying for someone to fix your car or make you a hamburger, even though technically they all involve the offering of services.