I am not negating that, but I would like to mention one thing. Even in places like MIT or Harvard etc, most students usually don't ask the questions. This is evident from video recordings of MIT lectures on YT. For most students, for the most of the time, it is a one way communication from teacher to student.The live, real teacher in the classroom WINS. Real interactivity at its best is when and where the actual students and the actual teacher are in class together. Students may (if allowed) interrupt to ask any questions during lecture time. All that TV stuff may work as a supplement.