Look at the chart for non-major interest in upper-level CS classes at Harvard: operating systems has no interest; "data science" is surging. Andrew Ng's machine learning class has more than twice the enrollment of computer architecture or software engineering (which is a particularly pathological case, since by definition, nobody else can teach Andrew Ng's class).

This is not general-interest demand. Students are hopping on the bandwagon, and picking the classes that sound like they're the shortest path to a high-paying job. About the only thing colleges can do right now is offer more of the hot classes via lecturers, and wait for the crash. Universities don't hire (lifetime) tenured faculty based on short-term enrollment surges.