While it may have taken Nintendo a few years to jump on the HD bandwagon, it seems the company doesn't want to be in a position where it finds itself being left behind again when it comes to the latest trend in consumer technology.
In an interview conducted by Mercury News, Nintendo president Satoru Iwata clarified the focus of the company and the Wii U's 3D capabilities:
If you are going to connect Wii U with a home TV capable of displaying 3-D images, technologically, yes, it is going to be possible, but that's not the area we are focusing on... When it comes to 3-D, we already have the 3DS, and each owner of the Nintendo 3DS is capable of viewing 3-D images. However, when it comes to the home console, it depends upon the availability of 3-D TV sets at home, which, unfortunately, is not expanding enough. And rather than pouring a lot of energy into that kind of area, with the Wii U we'd like to focus more on each Wii U owner being able to have an equal opportunity to enjoy it.
Although the architecture of the console is not yet known in its entirety, it appears to be possible to update the Wii U in the future ― as it doesn't sound like it's capable of doing so out of the box ― in order for 3D visuals to be outputted.
Whether Nintendo will ever arrive at that bridge or not, it's good to know it is capable of crossing it if and when it does.