The reason why Nintendo put out so many unique and creative games is because they are targeting their customers and only one hardware.
Nintendo becoming third party and putting their games on PC would make very different games, less creative, less interesting. They would make open-world, story focused with cutscenes and pretty graphics games. They would eventually target everybody and not only die hard Nintendo fans who only want fun from their games and nothing else.
When you look at Rockstar and From Software success one would ask: they have success on PC! Well they are doing one or 2 games, using the same winning formula. They are not doing 20 different GAAS games on PC! And that formula has been created on console and all those games started as a Single Player game.