What's to stop Nintendo from adding non-Mario characters in Mario Kart games

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Takato posted...
https://youtu.be/3xX5KU19W-Q
Yet the Falcon gets no such love. A true tragedy.
ayy lmao ayy lmao || oaml oaml yya yya
ayy lmao ayy lmao || oaml oaml yya yya