Are you kidding me? You are definetly NOT thinking straight, first of all Nintendo will definetly do DLC content on it's own games, don't believe me, look at
THIS HERE, you are obviously against the idea but the fact of the matter is, why wouldn't Nintendo do DLC on one of it's biggest, best selling titles of all time? If you ask me, Smash is the perfect game to incorporate DLC, why? Because it offers extra stuff such as costumes, music, and possibly characters and stages and that my friend would reel in lots of money since it also happens to be a major selling game, plus it gives the ability to add content that would otherwise never be included during launch date.
My question to you is, why wouldn't Nintendo take advantage of such a feature that Iwata clearly shows interest in doing? Why wouldn't it be suggested to Sakurai at all? I ask you this.