Earlier quoted context omitted.
The main problem is that great courses require great faculty to create and manage them semester by semester. Udacity and the like are built on the premise that we can scale up a professor's reach by orders of magnitude. But you can't do that without losing quality. The state of online course software is such that in most cases it's a hindrance, rather than a help. Software should make our jobs easier, but for profess…
The assumption that classes should be taught on a semester ("seat time") basis, with everyone starting and stopping at the same time, is a professor-centric view of the world. A student-centric view would use technology to help students have an educational experience around their own schedule and needs (e.g., varied pace; reinforcement or skipping where appropriate).
The issue is that, if you take away all structure, you also tend to take away most real-time interactions (which admittedly are a serious weakness of MOOCs anyway) and you end up with an experience that's not much different from reading a book and/or watching online video talks/lectures/documentaries/etc. or, indeed, just doing some project. Of course, there's nothing wrong with learning that way. But, at some point, you then go--why bother with this MOOC thing anyway if I just want to learn something?