For one thing, Sakurai might consider adding Banjo to be a less interesting opportunity, when he could be adding the biggest mascots from Microsoft like Chief and Steve. He might have viewed Banjo as a big opportunity back in Smash 64/Melee, but with the current situation, he might choose to pick Steve/Chief over Banjo (characters that would better represent Microsoft as a whole), in sort of the same way that Simon was chosen over Bomberman (Whose IP was also acquired by a big company Konami, whose franchise is also minuscule compared to the big franchises like Frogger, Castlevania, and hell even the Yu-Gi-Oh videogames). We gotta look at all of the possibilities that could have gone through with Microsoft instead of just narrowly seeing one path of Sakurai only approaching Microsoft for Banjo with no roadblocks at all. Thinking only one-way and believing that to be the only possibility could lead you to a path of disappointment.