You keep saying that they are rewarded for doing a hard content.
That has been debunked when Criterion Dungeons came out. No one does it as much as Yoshi and co. thought they would because the rewards for clearing it were... very underwhelming. People don't play because it is "hard content" people play for the rewards so they can show off and brag like: "I cleared this!"
Those very few people that do hard content just for the funsies, I commend them but you gotta look at things realistically that majority of people that do hard content is because they want that carrot on the stick.
