Income becomes secondary if the game puts in a competitive sense into the player. Every human being loves being called the "best of the rest" and being shown a top number on a ranklist, it becomes like an addiction to them and a false sense of being in control over others.
I disagree that people in play to earn games compete to be counted as best of the best and earning is not their motivation to play. I might be wrong, but all play to earn game I've faced are rather primitive. They dont even stand close to regular PC/Console games with competition element (such as CS:GO or strategy games). The only ranking that matters in play to earn games is the amount of earned.