As a counter example I've signed up for 6 and completed 4 (Machine Learning, Mobile Robotics, Cryptography I, and Introductory Python Programming). Granted a couple of those I only partially completed the first time and went back and took again due to time constraints. I think the whole article is based on a false metric (percent sign up vs complete). Here's the real metric, which is cost/student to successfully enable a student solve problems as required by an employer. I think the book is out on this one, but having interviewed 100's of engineers and made about 100 hiring decisions over a 25 year career, I certainly would not care how someone learned to do the work, and if you can answer all the technical questions I have on a subject that's good enough for me. If you have to rely on a accreditation to know if someone can do a job for you I think your career working as an engineering manager will be brief.
I've used remote learning based on other methods (itunes U, MIT open courseware, and even back in the day grad courses on remote sites via closed circuit tv). With the exception of closed circuit TV, a good MOOC course is much better than the other forms because you get early feedback on where you are missing material. I looked at the paper in the article noting that the "non matriculated" classes are less effective than the "matriculated" classes. No duh. But the point is the non matriculated classes are free, or very close to it. You just need to be motivated.
I looked at the guys website (thinkful), I have to applaud the fact that they are trying a startup to teach people, but the fact that they want $300 a month for the service and the way mentor's are hired makes it look a little like a multi level marketing scheme. The advantage of Moocs is they scale up and it doesn't matter if the class has 10 students or 100,000. Maybe I'm just old, but it seems nobody ever "mentored" me in engineering school. I went to lecture, read the books, did the homework and took the exams. The only difference I see with Mooc's is a computer is doing most of the work that was done by the Professor and TA's and no partial credit on exams.