That could be said for most games. There will always be those that take games to another level (like that guy who's played insane amounts of Bubsy, or speedrunners), but it doesn't mean that they are the main audience. I could go crazy hardcore for Mario Party 10 with a bunch of other people. Trying to make it into something competitive and after making up rules and finding out new ways to play the game, creating something mildly competitive. But I would never expect or get mad that Mario Party 11 didn't deliver that compeitive balanced gameplay that I and bunch of other people made Mario Party 10 into.
You kind of make it sound like (apologies if that's not what you meant) that being more hardcore gives you a better perspective on how the game should be designed. What it comes down to is that Smash has always been more of a party game than a competitive fighter. That's how Sakurai and team wants it to be and that's the game they are creating. They do however try to cater to that hardcore Final Destination fanbase as well but it's never been the focus.
You mean that unbalanced stage?