Those stats are heavily skewed.
You can't just stick Mario in a cart and claim it to be a different franchise. Also, you're missing quite a few games from the Nintendo list, I'm not a huge Nintendo gamer and even I can see some obvious emissions like Mario Party and Paper Mario. Factor in handhelds and that list is going to look VERY different.
The number of games isn't even the problem either, most of the IPs you listed on the Wii are at least a decade old, whereas the ones in the Sony and Microsoft section are fresh IPs.
Mario Kart IS a differnet franchise, it's a completly different game. It is, how ever, the same IP.
That's true actually, my bad.