theres a lot at play here, but one of the reasons besides the marketing stuff is that smash arguments are basically the regular /v/ arguing over games condensed into a single thing, arguing about which games are relevant, irrelevant, which characters are literally who, etc. It's arguing about how things you like are amazing and things you don't like are awful. >>2104
Competitive smash for modern smash games will never evolve until Sakurai realizes that you can allow complex mechanics to exist in a game and not have it effect casual players that much at all. He doesn't need to have it be melee 2, but hes so afraid of alienating people that he just won't do it.