You mean the part where you only need 5 people doing the job instead of 50?

> mathematicians by calculators

Calculators didn't replace mathematicians, they replaced Computers (as an occupation). To the point that most people don't even know it used to be a job for people.

I say calculators but there is a blurry line between early electronic computers and calculators. Portable electronic calculators also replaced the slide rule, around the late 1970s, which had been the instrument of choice for engineers for around 350 years!