Don't you only get paid if someone else actually uses what you patented? I have never seen that happen with patented game mechanics. If the mechanic is patented by company X, company Y simply won't use that mechanic. Who the hell else had playable loading screens when Namco still held a patent on them? Who currently has a nemesis system outside of the Shadow of Mordor games, which is patented by WB?
The nemesis system wasn’t unique when it came out, plenty of games have similar mechanics, obviously there is a distinct mechanic about Shadows of Mordor that other can’t copy with the patent, but it hasn’t affected nemesis systems in other games.
They don’t pay, because there’s usually another way to make a very similar system that doesn’t infringe.