I'm talking about the original Paper Mario and Super Mario 64, both for the N64. It was my intention to compare them, not equate them, precisely because they aren't much alike at all and demonstrate that even within a franchise you can be quite unique, which is more or less as good as a new IP and Nintendo has shown itself repeatedly capable of doing that. What's not good are games like the last several Mario games since Super Mario Galaxy and New Super Mario Bros. DS, which have all, again more or less, been the same. (Note Super Paper Mario (fairly different from the original itself, and Thousand Year Door as well) was released before Super Mario Galaxy.)
Nintendo is responsible, yes, so long as they're a games company and not a hardware company. Sony does it, Microsoft even does it to a lesser degree. There was not a single new IP that Miyamoto worked on for the Wii apart from Wii Sports. Wii owners did get 1.5 new Zelda games though, and as a Wii owner of course that pleases me. Again, nothing wrong with using a franchise.
It's also in their self-interest to make new IPs, if for nothing else than to show what their console can do which is just one extra selling point for getting third-parties on board. I would have thought they learned their lesson with the Wii from its final couple years, but how's the Wii U doing? A lot of third-party developers (notably in the news recently, EA) aren't getting invested in that at all, especially with the PS4 and Xbox One on the way, and especially with the rise of mobile gaming. And there is still the audience that's always there, the glorious PC Gaming Master Race! (My own bias. Though the consoles have made it this way for me by no longer catering to the gamer.)