Sony and Microsoft are more or less two computer/electronic entertainment companies that have now turned their sights onto the the ever growing video game console market (thanks to mainly Nintendo's efforts), mostly just "hosting" thrid party (exclusive) games to draw their coustomers. It wouldn't be any different if, say, Apple or Samsung suddenly began making their own home consoles. Nintendo however isn't a computer/electronic entertainment conglomerate, they simply make games, their only hardware being the console you play those games on... nothing more (no CD players, televisions, laptops, digital cameras, etc., or anything else like that) more or less just games (with the occasional console add on... i.e. Gameboy Player, GBA link cable, and various controller pariperals, etc.)
IMO the real winners in the console wars is the company that is able to produce the most thrid party exclusives. I don't care how good Nintendo's games are, when you step back they can only make so many games and so many kinds or games. More thrid party exclusivetitles equals more games and more variety in gaming. That is why PlayStaion 2 ruled over the current generation with an iron fist, they simply had more exclusive titles and sheer volume to choose from (the same reason why Nintendo was so popular with NES and SNES, simply due to lack of competition Nintendo had totoal rule over thrid party games, also why Nintendo is still winning the handheld front, more thrid parties back Nintendo).
It really don't matter how well a first party is, a first party is after just one company and they can only make so many games at a time. In Nintendo's case their first party games are all stellar, but there still is no reason why thrid parties can't also be developing stellar titles for their console as well.