> Lecture delivery is not anywhere close to 100% of teaching a university class.

Absolutely true.

> Lectures have to change over time, both because you can do better with practice and because the material and real world change.

This is obviously going to be true for vocation-focused classes, but am I wrong in thinking that this is going to vary from field to field? Once you nail down your Math 101 lectures, do you really need to change them?

Also, this is not a real argument, but I have seen universities where lectures were given by a professor, and Q&A office hours were provided by a TA. I imagine that some universities are thinking that they can have a professor write a lesson plan and record lectures, and then the class can be run in perpetuity by a team of grad students. (Cue laugh track.)