6 years is not a "short life cycle" for any system. At worst it's above average.
3-4 years is where one can cry about a short life cycle.
The Wii U or Wii 2 or whatever they wanted to designate it as would've failed in 2013 or 2014 or whatever. The brand was stale and every system had the same mini-game motion games, if anything Sony's Move controller was by far the best motion controller any of the three released.
If there was any market juice there, they would've just copied whatever it was, things were never going back to the way they were pre-2010 when Wii was the only real motion gaming platform and you had no choice but to buy it to get that type of experience.
It's not a blue ocean when every other console manufacturer is doing the same thing. It's not a blue ocean if everyone and their grandma has touch screen games on their smartphone sitting in their pocket at all times.
I don't think delaying the 3DS and Wii U for a year would've changed anything and you can't redesign a hardware concept in a year's time either.
Nothing you said holds any value when Just Dance 2020 was still released on the Wii. Even with Nintendo's negligence, the Wii still comfortably outlived its motion control competition. The continued yearly release of the Just Dance series proves two thing about the Wii: The console and its concept had much more juice left in it that Nintendo wanted to grant it, and the so-called casual audience wasn't fickle, but reliable.
If it now needs to be explained to you why the Wii U was nothing like the Wii, then it would be just another case of your ineptitude to recognize the obvious. Normal are able to tell the difference between a motion controller and a non-motion controller, and they are also able to tell that the vast majority of games for any given console will be designed for its standard controller.
Just Dance is the exception, not the norm. Just Dance, shovelware crap that comes out every year with minimal effort put in, is one thing; Mario, Zelda, Xenoblade, and Nintendo’s other franchises is another.
The fact still remains that Nintendo’s resources were limited and if they had spent any more of them on developing games for the Wii post-2011, those are less games coming out on 3DS, let alone the Wii U.
Hindsight: 20-20 The Wii U was going to flop regardless and there was nothing that was going to save it. The 3DS on the other hand? That could still have been salvaged and it was. If you took some of the early 3DS games like NSMB2, FE: Awakening, KI: Uprising, Tomodachi Life, 3D Land, and Sticker Star and put them on the Wii. The 3DS was already struggling enough to gain traction. How much more fucked would that system have been if it lost some of those titles?
Not only was the 3DS going to sell considerably less. Some of those titles I listed would have sold considerably less on the Wii than they did on 3DS. Galaxy 2 had already sold around 5 million less than Galaxy 1, and that was when Wii sales were still relatively healthy. So what would 3D Land have done on the Wii at a time when the Wii was all but dead post-2011? How about Uprising? Does Sticker Star still do 2.5 million?
What about Fire Emblem? Awakening was supposed to be the last game in the series until it blew sales expectations out of the water, being on the 3DS when its sales and momentum was at its peak, was one reason why. Does Awakening still reach those levels on a dead system where its last entry, Radiant Dawn, didn’t even reach .50 million when the Wii was at its early peak? Congratulations, Rol. In your scenario, Fire Emblem is dead.
The only game out of that bunch that I could see doing better would have been NSMB 2.
But one game doesn’t justify the underachieving performances of other games and especially underachieving hardware. 2011-2023 was the one time where Nintendo posted operating losses, how much steeper would those losses have been if they went down the route of giving more support to a system in its way out?
The writing was on the wall. It was time to move on.