And would it make any difference? They always relied on 3rd party power. Sony 1st party offers are more like an extra than a real need.

They could, but I can't see it happening. Nintendo never evolved from their 80s mindset. They use old thinking to compete with aggressive adversaries. They damaged 3rd party relations, they associated their image with kids, they did everything possible to create a product that isn't desirable by teens and adults.

I think they really relied on brand recognition for this generation.  They thought that people would buy a WiiU because they got WII's.  

Buyers however seem to be very very well informed and dedicated to getting the console that gives them the best value for the games they want this generation.   Many users seem to be skipping this generation altogether.  

Nintendo WII sales were like a steam roller last gen.  I think they drove their own insanely high sales...as in people bought because so many other people bought.   It was the "must have" for years.    I have two neighbours who don't even play games that got one just in case.  The price point was so nice that it was a no brainer to have one for those couple times people came over and did some dancing or such.   Nintendo found a totally new market that nobody even knew was there...the casual gamer...and they murdered MS and Sony with it.  Both companies have responded though and that niche is shared by all three.

The only thing that is going to make a runaway brand (sony, ms or nintendo) is if they somehow find another niche.   I'm going to suggest that one of them is going to have to suppress their fear of being hacked because of opening up their hardware but a console allowing Apps might be that niche.  One of them allowing Apps within a virtual machine would do it with the least amount of risk....

It would be interesting to see if Microsoft can manage to release a generation where they don't shoot themselves in the foot.(HD-DVD with 360 and the hardware lag/forcing of Kinect with XB1)

I think that tablets and smartphones played a big role with casuals. It's easier to rely on a device you already have to play the ocasional game. Maybe MS and Sony adding motion sensors did the damage too, since it removed the advantage the Wii had. One thing that PS4/3 and X1/360 have is that they are great multimedia centers, something none of the Wiis excel. You can play your Just Dance and watch some high quality streams all in one place.

MS already have big plans for apps on the X1. Windows 10 will unify the OSes and they will have universal apps. X1 already uses virtualization and runs 3 operating systems: one hypervisor that hosts the virtual OSes, one virtual OS for games and one virtual OS for apps.

MS has the habit of shooting themselves in the foot and it's something they share with Nintendo. I actually think that most of the succes Sony sees with PS is simply because they are normally the ones that don't screw up or at least don't do it in an unfixable way. The others, when they screw up, it's usually a mistake that they will carry for the entire gen.

We could also look at it this way:

With what is going Nintendo to support Wii U with after 2015?
Only 1 Mario Kart, 1 Smash, 1 2D Mario, 1 3D Mario (because as Miyamoto mentioned, the new one will come only next gen), Zelda is releasing next year (so a new one only next gen aswell), per generation.

What big hitters are left that can sustain the fall to even lower numbers, when those above didn't kickstart Wii U sales (with the exception of Zelda, yet to come out)?
Also, next year you'll have Starfox, Xenoblade, Mario Party 10, Yoshi and Kirby. Not to mention, 2 new franchises: Splatoon and Mario Maker.

The big franchises left are Mario Sports games, Animal Crossing, Paper Mario, Fire Emblem x SMT, Metroid and Pokémon (most likely Pokken).
Assuming each one has a game coming out in 2016, will that be enough for 2016?
If this year's DK TP, MK 8 and Smash didn't do a lot for Wii U, it's not the 2016 line-up that will. Especially for a console in it's 4th full year.

unlikely