And yet how many I.P's that are created by the other companies have healthy lifespan? Half the new I.P's created are never heard of again or die off within two generations.
And yet even something like Metroid chugs along pretty well, and there is interest in things like F-Zero (They did try to set up a game with Criterion at the early days of the Wii U), and Star Fox (Star Fox Zero was a thing, even if it wasn't super successful it was an attempt to bring it back up).
I wouldn't say that Nintendo's games in general have a healthy lifespan considering that there's not many new IPs and 3rd party games to compete against on Nintendo's consoles. They might not do so well against alot of competition. Also, Nintendo likes to cater to gamers who are more nostalgic.
Alot of established IPs on any console were once new IPs. It doesn't matter how many new IPs fizzle out or put in the storage closet for later. They have to start somewhere. Alot of the best games and game mechanics/features have come from this.