It appears that the one group that they do service are "non-traditional" students and the problem appears to be keeping their attention.
The report names student engagement as a prominent theme. Many students enrolled in MOOCs are nontraditional, so making sure that they are engaged and able to succeed in such a course is even more important. Figuring out how to maintain students’ interest during an online course when “a distraction is literally just a click away” is another important element, Mr. Siemens said.
So putting things on line has some potential drawbacks that researchers are now addressing. Note too the audience, "non-traditional" students. It seems that for the regular college crowd MOOCs may not be on the agenda. Effectively, MOOCs are now filling the role that correspondence courses filled in the pre-digital era. And it seems that they are finding problems analogous to those that such courses traditionally encounter; keeping the student's attention focused on the material. This does not strike me as very surprising. It was never clear to me why presenting the material on line on a screen should make it more engaging than doing so in a book on your lap. At any rate, the discussion goes on, this time with much less hype.