I looked at the article written by Barbara Oakley which was cited in the current article. [1]

MOOC deniers are asking if they a) adequately satisfy the requirements from education, an important part of which is the actual completion of the course and b) are economically viable.

Let us leave aside the question of whether you decide if it is a good idea whether to gamble at Vegas by talking only to those who hit the jackpot. [6]

Barbara Oakley's defense seems to be:

1. "Look at how many people can now learn this stuff" [2]

2. "Look at all the new and amazing things which happen when students can play, pause, rewind and resume the lesson, or when teachers can use all the technologies at their disposal" [3].

3. To fellow instructors: "Please try a little better. The problem might be the way you teach"

And remember that teaching someone how to learn is not exactly at the same level of rigor or conceptual difficulty [4] of teaching someone calculus. If you have ever seen a screencast of some really dense material [5] from some really smart people and see them struggle to "hold the stack in their head", so to speak, as they present their thoughts in public view, you know the process starts becoming seriously challenging as the subject increases in difficulty. Here are some quotes from Barbara Oakley's articles, which I think are good examples of things which don't scale very well as the material becomes more rigorous.

"Good online courses make students feel professors are speaking directly to them. A teacher’s direct focus on the camera translates as personal attention in the videos. Students develop a sense of familiarity; we are often seen as friendly private tutors. It makes us more approachable and “listen-to-able.” It’s not that we’re replacing teachers in a classroom. It’s that we serve as additional personalized resources, despite the fact that we’re explaining at massive scales. And I should mention that every single video lecture I give in our MOOC is the best lecture on that topic I’ve ever given in my life."

"Terry and I made “Learning How to Learn” for less than $5,000, and largely in my basement. I had no previous film editing experience—in fact, I could barely click a camera shutter. Much of the moving imagery for the course was created using simple PowerPoint slides. So I would issue a challenge to MOOC critics. Make your own online course. Film the most interesting, most insightful lecture you’ve ever given in your life. If you don’t think your lecture is good enough, reshoot it until you’re happy. Make your video available for millions of students around the world, not just the privileged few in your classes. Come up with questions for a quiz on the mistakes you most commonly see in your classes. You will learn more than you know about the outreach and capabilities of MOOCs. More importantly, you will exemplify a wonderful openness for learning to students everywhere."

[1] http://nautil.us/issue/29/scaling/why-virtual-classes-can-be...

[2] "She cited a range of groups who are promoting the course from the California State Prison System, federal K-12 teacher certificate programs, as well as refugee camps in Somalia and Sudan, where she asserted that students threatened to overwhelm the meager Internet bandwidth available in those countries." - from original article

[3] "I would venture to say most MOOC deniers have little experience with creating and teaching online courses. The reality is MOOCs can be artistically and technically fascinating and can have terrific pedagogical advantages. This is particularly true in the fraught area of STEM (Science, Technology, Engineering, Math), where difficult explanations often cry out for a student to replay a portion of a lecture, or simply to take a pause while comprehension works its way to consciousness. "

[4] For example, I would like to know how the students assessed the satisfactory completion of the material to decide whether they are, indeed, better learners. And then compare it with whether their actual learning rate improved in their future endeavors.

[5] https://www.youtube.com/watch?v=nfoudtpBV68&list=PL4LJlvG_SD...

Edits: some edits for readability

[6] I mean this in two senses. One, of course, is the choice of subject, among thousands of possible ones - something as meta as "Learning how to learn" has a few built in advantages when it comes to measuring popularity. Two, I don't mean it in the sense of a skill-less person getting the luck of the draw to achieve the desired result. I mean in the sense of how there are bound to be a few jackpot winners in a large enough sample, and studying them is misleading because the takeaway messages are not universally applicable.