These are just wild guesses, perhaps its 90% kids/10% nintendo fans or 10% kids/90% nintendo fans or any other share between. And correlation does not imply causation... the fact that Mario Kart 8, Super Mario 3D World, New Super Mario Bros. and Wind Waker HD have great sales and "cartoony graphic" doesn't proof that the cartoony look is the most important factor for the great sales. Maybe they sell great because they have great gameplay or because Mario and Zelda games get great reviews or because Mario and Zelda games have a great reputation or because Nintendo was advertising the heck out of them... or a combination of all these reasons.
So please explain why Bayonetta 2, Assassins Creed 4, Need for Speed Most Wanted U, Mass Effect 3 and much more didnt sold good. They good gret reviews too. And special bayo2 is exclusive to wii u.
Easy, they had neither Mario nor Link as main character. ;)
But if you are really into the "cartoony" cel-shading look in AAA games... there are many cel-shading mods for PC games and PC-emulators out there:
