It is weird to assume that Daisuke's fanbase will move on to Yuzuru, imho. Other than that they're the most succesful male skaters of Japan and overlapped in the same era I don't see much similarity in looks, character or skating style. Yuzuru might attrack different fans (maybe the mentioned younger idol fans?) than the aunties that follow Dai. Not every figure skating fan just follows the next skater when their favourite is gone. If Mao retires there will be a big big gap left as well. Japan does have it's own issues in that area I assume. Saitama is a pretty big stadium and seemed full to me at least, and I'm sure sooner or later Yuzuru and others will be able to fill up the stands as well. Maybe tickets will be easier to get then. It seems to me that the balance is slowly favouring the Russian skating again, but who knows.