Ogre: You forgot Virtua Fighter, One Must Fall 2097, Destruction Desire, Dogma, Eternal Fighter Zero, Melty Blood, Mind Arms, Valkyrie Fight Tag (I'm aware that half of those are freeware titles) and many others. Seriously, though, listing games a system does NOT have means nothing, there will always be a whole lot of games a system does not have. Hell, except for Virtua Fighter none of the games I just named are on any console, they're PC-only titles (well, Melty Blood has been ported to the Arcade but that doesn't really count)!
Bill: So if someone would make a game where you run from room to room killing zombies and solving the occasional easy puzzle without any form of story you'd hold that as high as Eternal Darkness? Story creates emotion and emotion is a part of the gaming experience. Take Ico. I don't believe that game got all of its praise for innovative gameplay, it's praised for the experience it delivers. Realize it, themes and stories have a tangible effect on how a game is perceived and with entertainment perception is reality.
Creating a new franchise means discovering new things. Discovery is fun. I'm one of those people addicted to absorbing information (yes, seriously, you can get addicted to the substances released when you learn something). Reliving an experience is nice once in a while but without new material it becomes less fun.
Also, you shouldn't act solely out of necessity. Nintendo doesn't HAVE to create franchises, hell, they could use stickmen as their characters, but that doesn't mean they shouldn't do it nonetheless. Acting upon necessity makes you only take the minimum effort required and that's what Nintendo is often blamed for: They make a memory card, sure, but it's only 59 blocks. But hey, it's a memcard, right? You can save stuff on it so it's enough, right? They put their old NES games on GBA carts and they sell, why do anything more than the bare minimum? Hell, they gave third parties the option to make online multiplayer games, right?
Sometimes the bare minimum isn't enough. Well, "sometimes" is an understatement.