When the Wii U is in the state it is in. The 3DS is just finally fully recovering from a disasterous blanch, and the Wii went out with a whimper.
Does it make them feel better?
I can't really comment on the issue of other systems failing... I don't talk about that, because a system can't fail before anything is known about it. Indeed, I tend to try to predict the best course of action for each of the three.
I do say that Vita is failing at the moment, but that's only because it has something to compare to it - namely, the 3DS. And failing doesn't mean failed.
However, the Wii U's state isn't quite as dire as some people, such as you, suggest. Need I point out that with the exception of the Wii, all of Nintendo's recent systems have started out weakly, and then started selling much better once certain software released for it? It's true of both the DS and 3DS. What made the Wii stand out so strongly was that it had the necessary software at launch - Wii Sports, primarily. And while Nintendo Land may be a great game, it's really more of a retro-focused game than an expanded audience game, which is why it's selling well, but not driving software as much as Wii Sports did.