I think it's pretty ridiculous that anyone would call Sakurai a jerk or accuse him of being "too egotistical" (which is something I also take issue with since 'ego' should not have the negative connotation that it does). The man is a genius. Regardless of whatever flaws you have with any of the games he makes, his brilliance and work ethic make him one of the last great prime movers in the video game industry. He has every right to want to have full control over his magnum opus. A producer, a man of the mind, finds motivation in the quality that he creates and will do everything in his power to protect what's his and maintain the level of quality that only he can bring.
You can bet your ass that if anyone but Sakurai took over Smash bros, every single character that was added would be done so to promote new games. Empty and shallow flavor-of-the-month characters would be the norm, and each iteration would be a revolving door. Totally undeserving but popular characters like Waluigi (calm down, I'm just making a point) would be playable immediately. We're lucky that someone with such massively high standards is helming Smash.
Sure, he's made some mistakes, but that happens with anyone. What really makes a true prime mover is that they learn from those mistakes. Sakurai has a team helping him balance and axed story mode. In fact, his at-times painfully overexpressed humility is possibly one of his biggest flaws. He created one of the greatest (or greatest) video game franchises in history, and it is his right to be immensely proud of that achievement.
Moral of the story: Ya'll mother****ers need Ayn Rand.