[jjoonathan]

The problem is that coursera classes thin out dramatically as you reach the graduate (or even middle/upper undergraduate) level of whatever topic silo you are interested in. CS might be an exception, but the offerings in large swaths of chemistry and physics are extremely meager and I imagine that's the case in, say, biology, the humanities, etc.

Universities have precisely the opposite problem: professors love to teach high-level classes in their fields of interest but they don't particularly care for the intro-level classes.