Yes, the other console manufacturers are looking at 4K hardware, at least partially because Sony has a vested interest in pushing 4K so they can sell more TVs and Blu-ray players. And Microsoft needs to keep up with Sony because they're competing in the same space.
Nintendo has made it clear that they aren't competing in a straight-up power race with the other console manufacturers. And at the moment, 4K adoption is low, and the benefits of 4K are (and will continue to be) minimal at normal viewing distances that most people use. Sure, it's a great bullet point, and maybe Nintendo will suffer because of it. But they simply can't compete with the other consoles in raw power.
So instead of looking forward to 4K, Nintendo is looking forward to a unified platform for console and portable use cases. They are looking forward to a console that has two-player support out of the box. They are aiming for a different goal than the other console manufacturers, and frankly I think it's a smart move, given that the market probably can't support three consoles that don't have much differentiation.