For example, when I started college in the 80's in many colleges CS was still a bullshit curriculum in some respects. They learned a little calc, a little science, but not really enough of either to develop the thought patterns (or even the vocabulary, really) of the fields. Kids who knew they needed to do something technical but didn't have the background or aptitude kind of failed into CS.
As CS (quickly) matured, so did its instruction, and before long it was the place where the smart kids went. Their ideas cross-pollinated with the rest of science and "suddenly," because it was cheaper to gain efficiency by making the software better than by making the hardware better, CS types were in demand.