The disillusionment kind of kicks inn when you take on your first internship, or full-time position, and discover that there's a huge gap between what you learn and what you actually use.
It is unfortunately even worse when it comes to grad school - some people are in job positions where you're required to hold a masters degree, if you want to climb the career ladder. My own MBA was a pretty expensive diploma that only served as a door to more senior positions. Pretty much all the topics I had, I had taken before, or had been exposed to through work - maybe a whole 10% of new / fresh knowledge...and I'm the intellectually curious type.
So I'm not at all surprised that a bunch of students today will more or less offload all their schooling onto these models.