No one does or really even tries to beat N at platformers. Galaxy, SMB3, Super Mario World, SM64,Odyssey and Super Mario Bros (1983 !) are essays in masterclass games. Plonk anyone of those games in front of me and i am a happy gamer.
RARE back in the day (pre MS aquisition) did at times beat Nintendo. Not intentionally, just RARE's content was so good it rivalled what Nintendo themselves was putting out. A huge number of RARE games are masterpieces. I guess I'll list some.
RC-ProAm, Snake Rattle 'n' Roll, Battletoads, Wizards and Warriors 2/3, the NES port of Sid Meier's Pirates, all 3 Donkey Kong Country games, Killer Instinct, Goldeneye, Banjo Kazooie, DK64, Jet Force Gemeni, Perfect Dark
Today, though you are correct. A few try to put out more family friendly games, like the new Ratchet and Clank, as well as some of the other more cutsey games we've seen coming soon-ish.
The big difference is the studios that work with MS and Sony makes games for specific markets. A game for FPS fans or a game for casual fans or a game for RPG fans etc etc. Nintendo's focus os more making games of differentgenres that everyone will like, even people not fans of that genre. Example? I really don't like driving games, really do nothing for me. However Mario Kart 8's appeal is so broad that it appeals to even a non driving fan such as myself. You don't achieve 20m sales of a game without it appealing to people who raditionally don't like that specific genre.
Why yould you or I or anyone not a fan of a particular game's genre, want to play a particular game?
Nintendo answers that question quite well. Other studios need to find answers to that question for the games they release.