People aren't meant to be yokozuna for as long as possible. They are meant to be yokozuna for as long as they can uphold the expectations placed on them. It's an honorific title that can't be earned by fulfilling a checklist of accomplishments, it's bestowed for remarkable accomplishments on top of a career judged worthy. As such, expectations are different for each rikishi. The expectations are high because they are supposed to represent the best in sportsmanship, as well as Japanese culture. Just because something is legal doesn't mean it's sporting to do so. That's why I get disappointed when Hakuho does cheap sumo. He still routinely shows he doesn't need to. When he genuinely needs to, he should go.