lecturing via videotape

I think this is an interesting concept:

Brad DeLong: The Future of Higher Education?

The post is about the Teaching Company, which records lectures onto DVD and sells them for individual education purposes. I've had a couple conversations with people in the last month or so about the state of undergraduate education at top tier universities (where freshmen are taught by professional researchers) and at public schools. In the university context, we've discussed expanding on the current class of lecturers, granting them tenure, increasing their salaries, and trying to correct the perception that they're failures. In public schools, the general perception is that salaries need to be increased significantly to create an actual competitive market for teachers.

Instead of both of these, why not use effective presentations on DVD, centrally designed and widely distributed, in the classroom in lieu of poor lecturers? Obviously I'd want to have someone there who could answer questions; it would also be nice to equip students with 'pause' functions so they could stop the presentation and ask someone a question. But it would require a lot less from the teachers, it could greatly improve comprehension and keep students' interests (because the presentations would undoubtedly be more entertaining and compelling), and it would be a lot less expensive. And you'd still need people to create and grade assignments. But the lecture is the most important part of effective communication, so this seems like a really efficient way to improve the quality of education.