The first time I heard "whale" mentioned in the video game space was at a GDC panel around a game called Puzzle Pirates, where the dev noted that the bulk of their in-game purchases were made by a small group of "whale" players. In 2003 purchasable skins, pets, hats, etc were pretty new.

Algorithmic optimisation will be the death of us.

Over-dramatic? Maybe, but this thought springs to my mind more and more.