There will be a scene yes but will it be entertaining enough for it to live? In Smash 4 it is very difficult to kill someone at even 150% and if people are bored then it won't live. I'm not saying melee is the only game but I just don't think smash 4 will cut it
I really think Smash 4 and Melee are two different games entirely. If people play Smash 4 like they would play Melee or even Brawl, they're not going to get very far. If I want to kill someone under 150%, I would be smart about it and not just fire smash attacks again and again expecting to kill someone. This is just me, but I normally kill opponents by doing meteor smashes, firing smash attacks at the edge of the stage, or simply using my up smash to send them in the sky (which kills enemies A LOT faster btw). And if this really does become a problem, Nintendo is free to patch this in future updates.
Anyway, I think Smash 4 is an exciting game to watch, but for different reasons from Melee. Melee gets all the hype because it's very fast paced with techs and all that, but Smash 4 will probably get liked because there is more focus in offense/defense strategy now that all of those complicated mechanics are simplified. In Melee you need fast fingers and strategy, but in Smash 4 you just need strategy. Also, because of the slower pace this game has, the strategies players make in Smash 4 will be far more appreciated.
The reason why Brawl didn't get far in the competitive scene is not because it was slow or boring to watch, it's because of game breakers like Metaknight, no hitstun, and the lack of combos. It just wasn't well crafted for a fighting game.
Smash 4 on the other hand, got rid of all the problems Brawl had. Therefore, we definitely should expect a competitive scene. Will it have a competitive scene as big as Melee? Probably not, but keep in mind that Melee also gets support from fighting game enthusiasts who only care about Melee and not other installments of Smash.
I have nothing against Melee, I just get annoyed when people think it's the true Smash (I know that's not what you're saying though). Melee is not the game Sakurai intended, Smash 4 is. However, I will say that I really appreciate Melee for having a large and loyal fanbase. Although Melee is not Sakurai's game, it's definitely the Melee community's game. I strongly support Project M for this reason.
Sorry for typing so much, lol. I just wanted to express my opinion on this whole matter. I hope I'm not pushing my opinion though.