> I think is the belief that a huge part of the value of a bachelors degree is growth you get living alone, in dorms, learning how to be an adult, etc. that aren't really part of a curriculum and would be hard or impossible to do online.

a counterexample would be the existence of respected schools with a large amount of commuter students, many of whom continue to live with their parents while going to school. I graduated from such a place. if you really wanted (in cs at least), you could only show up in class for exams and still get an A if you did all the homeworks and projects. this school is one of the most heavily targeted in the state for tech recruiting.

> In addition, I know that a massive number of people who take online courses (just the individual ones from Coursera and the like) tend to drop out, so maybe they colleges think that if they had an entire 4yr degree online almost no one would actually graduate (which may hurt their rankings or they dislike for some other reason that doesn't bother for profit colleges).

this is a bit more convincing. online schools already have a stigma since the originals were almost (or actually) scams. probably no one want to take the risk of offering the first online degree.