The one-size-fits-most nature of online education goes against the "customize your education at scale to learn" which was an earlier anticipated advantage about MOOCs. Specifically, adaptive learning and being able to accommodate a variety of learning behaviors and styles. "Learn at your own pace, in your own way, on your own time but still within bounds to the rest of the class" kind of thing.

I remember when Stanford launched online CS courses in the mid 2010s, that it was thought they'd have the best of both worlds and their in-person, offline course offerings wouldn't be affected. (Diluted down to the lowest common denominator of student, which now included online learners who weren't Stanford students per se.) Well, over time, turns out double duty-ing course material for online and the "regular" classes crept into all education for instructors. Which meant the courses with online equivalents became easier across the board. Thus, the target audience for everything shifted.

Again, with acknowledged intentionality, I don't really have an issue with this (which you could crassly summarize as "dumbing down" the course offerings for convenience's sake) -- except that from my vantage point it was an unforeseen consequence of part of the online and MOOC push.

Obviously, I benefited from online courses in my mid 20s and so I look at their rise with nostalgia and through a rosier lens than many. However, I also can't help but think that they ended up being not quite what was promised at the outset, which was better targeting in addition to expanded educational access around the world. Especially for students who thought they'd signed up for the more challenging materials and didn't want to be part of a grand new experiment.

Interesting that MIT OpenCourseWare will outlast edX, which for a few years truly did look like it was the future of university level education and beyond.