Here's a talk on making real world commercial games with Clojure on top of Unity.
you: Here's a talk on making real world commercial games with Clojure
video: dozens of game jam games have been made
Also worth noting that the idea is to use FP around stuff like the actual game logic, and then handle rendering details imperatively.
I mean, fucking todo apps are making "good money" in 2019, it does not mean that they are good examples. These kind of presentations should improve on the state of the art, not content themselves with something that was already possible a few decades ago. No one gets into game dev to make money, the point is to make better things than what is existing - be it gameplay wise, story wise, graphics wise...