I have thought about when Nintendo will stop making consoles too. The Wii U never took off at all... I don't remember seeing any advertisements at launch. Hell, I didn't even know it came out until about 3 months after it did. They have done a terrible job on it. I did end up buying it about 7 months ago because I saw a new Zelda title was coming out for it, however, right after I bought it, the NX was confirmed. We'll see how long they stick in the console market. I hope we can get back to the SNES days where Nintendo was king of the hill, however I don't see that happening when you have Sony doing as well as they are... not to mention Xbox.
I have owned two Wii's and one Wii U. All of them have exhibited problems in the cd drives -- difficulties reading CDs which are, so far as the eye can ascertain, pristine and clean. Eventually, they just stop working. It did take a few years' use for the Wii. It took only a half year for the Wii U. I've replaced the drives in the Wii units, successfully. I've cleaned the Wii U drive and it works better now. But this is a moving part and is prone to wear and practical experience has shown me that failure is too readily at hand with them. I've had some modest difficulties with cartridges in old NES and SNES units. But those are much, much older and they have sustained a lot more wear. Plus, I can much more easily clean them up. They still work fine after many years now. Plus, of course, they boot up real fast being ROM instead of relatively slow, rotating media.
3D was a big deal for a while. But it really sucks up huge amounts of resource (artists and programmers as well as hardware) and unless the game play actually requires 3D to work well, it almost always turns out that the effort that should have instead gone into a great game with excellent playability rather than into the overly complex art and programming and leaving game play more as an afterthought. That said, some games do use 3D well and it definitely makes the difference. But those categories are few.
I think most producers are actively out grabbing after the low-hanging fruit of Android and IOS phones (maybe someday Windows Universal, but who knows there?) Games there require hardly any thought at all and people make tons of cash selling almost anything. So who cares about crafted, thoughtful game playability anymore? Just pump out the next candy crush game. It's trivial to write, makes lots of money, and has near-zero manufacturing costs (transmission bandwidth is all.) I suppose all that has to simmer down on its own and find some natural level before anything else can work its way onto the scene.
I guess I don't know what the magic formula is. Is there one, now?