MOOCs, specifically Coursera and edX are moving away from the cohort based model to self paced model. The numbers according to both organizations prove that the strategy has been ‘succesful’. The primary reason for the shift is to move away from the traditional higher education semester based structure which does not work for a life long learner who might be at a stage of life where they cannot spend couple of months on a course and do not like to wait for the start date.

The flexibility of start anytime and work at any pace is fantastic but getting away from the
Cohort based model also has its problems. Cohort based model pushed people through the course and learning activities such that massive number of people were at a similar place with respect to the content at any given point. From the learning experience design perspective there are implications of  not having a cohort.

It has been four years since the MOOCs exploded in popular media but the platforms that are the basis for the instructional design have not changed drastically. They were less desirable versions of LMSs then and still are in spite of add ons/apps such as Talkabouts. The most important aspect of the MOOCs for learning which is different than the online courses is the massive number of people from all over the world, bringing their varied life experiences, attitudes, opinionsm and beliefs.
With the self paced model gaining currency, there is less possibility of having other learners at the same place as you are. That makes the most important aspect of the MOOC a moot point, reducing it to a less desirable online course.