A lot of people don't want a broad education. But they have no choice because they need to get the piece of paper to do the job they want.
The signaling game can be quite a pain.
It is a prisoners' dilemma in the way independent action leads to a sub-optimal outcome, too, and there is no easy way to coordinate across the labor market...
http://econlog.econlib.org/archives/2015/04/educational_sig_1.html