“Computers tend to replace one category of worker with another. There are two ways to get something done. You can find one group trained to accomplish things the old-fashioned way. Or you can pay another group to set up and maintain machines and systems that will do the same work with fewer employees – of the older category of worker. You are not really replacing people with machines; you are replacing one kind of person-plus-machine with another kind of machine-plus-person.

When IBM persuaded corporations to modernize their bookkeeping in the 1950s, businesses were able to get along with far fewer accountants, as they expected, but they had to hire more programmers than they had anticipated. Automatic teller systems also require programmers and technicians paid four times as much as bank tellers.

If things go well, banks need less than a quarter of the staff, and they come out ahead. But it is notoriously difficult to predict all problems, or their levels of difficulty, in advance. And one mark of newer technology is that while it is cheap in routine operation, it is expensive to correct and modify.”

Quoted from: “Why Things Bite Back: Technology and the Revenge of Unintended Consequences“, Edward Tenner, p.245 (Amazon link).