I think the key difference is that college is trying to set you up for life, whereas MOOCs are available for life. When I have turned to MOOCs in the past, it was because I had a specific goal in mind. Once that goal was met, which may have been half-way through the class, I had no reason to continue. In the future I may have a new goal that requires I finish the course, and I will do so at that time. There is no advantage to forcing me to have it complete within a set timeframe.
I think course materials should be there forever, sometimes being improved in some places, and discussion/reviews should be there forever as well.
So like a forum about a specific topic with learning materials available at all times. No deadlines, just people collaborating to improve each other's knowledge.
But when you are out of school, you have a lot of time constraints that you cannot afford to break. Forcing me to finish something before some deadline does not make me learn better; it only deprives me of the chance to learn.
This is rarely acknowledged.