Except that they do. Nintendo has the most diverse and enjoyable first party (exclusive) line up of all the consoles. You're not paying $300 for a single game, you're paying $300 to play all of their many high quality games, and their consoles are pretty damn cheap to boot.
Xboned on the other hand has... Halo, and Gears of War? (Rofl) Playstation has a more diverse lineup, but ultimately the majority of both games are on Xbox, Playstation, and PC. All you really need is one of those and a Wii U to have most of the best games.
In other words, deal with it or buy a Wii U. Nintendo is still extremely successful and they will most likely never go third party, certainly not any time in the foreseeable future.
In a worst case scenario where Nintendo stopped creating home consoles (this is extremely unlikely to occur, let alone any time even remotely soon), they would simply take all of their exclusives to their handhelds, where Nintendo essentially controls the market by a wide margin (besides cell phones, which are a bad joke to compare with and are not real gaming devices).
Posts like this are painfully sad to read. You're whining about buying a console because the games aren't good enough, because you want to play the exclusive games on the console. It's like dividing by zero.