The big issue for me is most of these courses aren't even full courses in the sense of a college course. Your typical college course will be 16 weeks and cover maybe 15-20 chapters (400-600 pages of textbook material) during the course.

Most MOOCs I see are basically the equivalent of 2-4 textbook chapters worth of material and even that materials is watered down greatly.

If I am going to spend the time learning something, I want to learn it at a high-quality level, not at a basic introductory level.