>I dunno why there is always the assumption in these threads that leetcode is being used

because it matches my experience. I work in games and interviews are more varied (math, engine/language questions, game design questions, software design patterns). I'd still say maybe 30% of them do leetcode interviews, and another 40% bring in leetcode questions at some point. I hate it because I need to study too many other types of questions to begin with, and leetcode is the least applicable.