In my opinion, almost everything that's happened is Nintendo's fault. Horrible marketing (I still have to tell people that the Wii U isn't just a Gamepad peripheral for the Wii) and poor launch titles are a huge part of it. People keep pointing fingers at third-party companies, but it's not their job to keep a system afloat. I still think that there's more to the story with the whole E.A. debacle (I wouldn't be surprised if the
Origin vs Nintendo Network thing was true) because they have actually gone out of their way to put down sales (mostly badmouthing, but
they also cancelled a fully-running version of Crysis 3), but other companies just did what they felt was necessary. Supporting the Wii U is a gamble.