Maybe it's just perception, Chozo Ghost, but I can't imagine Samus or Zelda in a kart or sports game. They just feel out of place. Though it may just be decades of seeing Mario & Co be in them that allows that to make sense over the other.
But I'm sure that is EXACTLY how everyone felt back in 1992 (or whatever year it was) when the first Mario Kart game was released. Kart racing was never featured in any of the original Mario games, and it just didn't make any sense at all at that time.
But even in those days, Nintendo was pimping Mario out into franchises that he kinda had no business being in. Like Mario Paint, for example, or Dr. Mario, or Mario's Time Machine. All of those were games that seemed out of place compared to the platforming stuff Mario was known for.
But that was then, and nowadays we take all of this for granted. If Nintendo announces a Mario Football game, who here is going to be shocked? But if you take Link and try to have him do anything like that then it is a shock, because it is completely new for him.
But the Zelda franchise has KINDA taken a small step in that direction with Link's Crossbow training. AFAIK this was the first time Link got pimped out instead of Mario and the gang, and it was a refreshing change. Hopefully there will be some more Zelda genre crossovers in the future.