A/N:  The reason why is because Sakurai has stated that manga characters will not be appearing in the franchise. It seems that Sakurai wants to keep the roster focused on the video game world.

“It is impossible for manga characters to join (Super Smash Bros.). While we can accept characters from other companies, we cannot, under any circumstances, take in anything and everything under the sky. That’s because (Super Smash Bros.) is a game that requires everyone’s cooperation.”

Zaydon:  Which means no manga characters like Jotaro Joestar, Luffy D. Monkey, Naruto Uzumaki, Son Goku, and Izuku Midoriya aren't coming to Smash.