First off, let me remind you that Sakurai always wanted Geno in Smash. He has not even said about Sora. At least Geno was already in Smash 4 as a Mii Costume, while Sora has not gotten in any Smash game, in any shape or form close to that.
That said, Sora is still owned by Disney, which was not even born in a video game company. That said, Kingdom Hearts does contain non-video game characters, and while it is possible to leave them out, they are still a part of that series, Mickey, Donald, Goofy and all. I am not sure Sakurai would be keen on having a series that is more or less about Disney's history or Disney movies put in a game series that Square Enix happens to make be put into a game that happens to be a celebration of gaming altogether. Smash is also mainly a celebration of Japanese gaming, and while there may be some Japanese stuff in it, Disney owns Kingdom Hearts, Kingdom Hearts has non video game characters, and more importantly, Disney is far more western than Japanese in many ways.
That said, plus other reasons, Geno has more that will get him in as a playable in Smash than Sora has. Plus, while Nintendo may be a business as well as Sakirau's company, I am sure the real cost of getting a character in is how much they are wanted by fans, and how they are fun to play. When did Sakurai even say he was adding them just to make himself and Nintendo more money, anyway?
Now, let this whole Sora thing go, okay?