I've seen that happen a lot with another character who really annoys me (it's not Mario).
A company chooses one specific character and says, okay, you're our mascot, so you get all the toys, games, etc.
And we're going to ignore all our other characters, even if they're more interesting.
I'm assuming that's what happened with Mario, Nintendo may have many other characters, but Mario is the one they've chosen for brand recognition, so it's all got to be about him.
Now having a mental image of Ralph having to beat down Mario for going "Turbo".