Who's losing their job over this?

I once provided a recipe for starting a high margin business. It went something like this:
(1) Find a customer pain that costs someone a lot of money
(2) Find a new, much cheaper solution that fulfills that pain
(3) Charge almost as much for your new solution as the old solution cost
Well, it has since been pointed out to me that the 'old solution' can, in many cases, be someone's job. You new solution is technology that automates and removes the need for that person's job. This has always been the case, since the Caxton printing press removed the need for monks to hand-transcribe new copies of books.

So the more provocative recipe for starting a high margin business might be a simple question: who's losing their job over this?