the people who bought a wii u bought the console mainly because of the nintendo games (mario kart, smash, super mario (maker)). 

Those games belong to Nintendo. Nintendo wont release them on smart tvs. So these games will never be available on smart tvs/smartphones whatever.

Call of duty, assassins creed, Grand theft Auto, The elder scrolls and co do all belong to third party companies. Those companies will bring the games to smart tvs/smartphones and co as soon as those systems got strong enough. Its already happening. Assassins Creed Identiy gets released next month on iOS.

So the 15 million people who bought a wii u will probl also buy the future nintendo consoles. Because thats the only ways to play nintendo games. At the same time the actual ps4 player will not buy a ps5/6. This will make the fusion nintendo console the most sucessfull, even if its just selling 15-20 million.

You have a very narrow view of things OP.

graphic quality might reach a peak, but the content within them wont.

it will sell more then the competition at this time (if there will be any competition left). Like Nintendos 10th gen console will sell better then xbox 10th gen and ps6. 

It will not be more sucessfull then older generations (ps2).

Don't be so obtuse.

You're acting like others can't make games like those. Sony chooses not to make games like Nintendo's games. MS chooses not to make games like Nintendo's games. It doesn't mean that either Sony or MS aren't capable.

If Sony or MS wanted to go toe-to-toe with Nintendo on Nintendo's playground, they would. There's just more money in their own playground, and if you haven't noticed, Nintendo's playground keeps getting smaller.

Not quite. I think a fair chunk of casual gamers bought the WiiU originally as a residul effect from the Wii's success with that audience. Obviouslt it didn't catch on all that much.

And I'd argue that there's more people out there willing to buy a PS5 based on brand alone that people willing to buy the NX for the Nintendo IPs.

This is crysis 3 running nativly on Nvidia Shield (an android tv box). It runs android and uses a ARM cpus (the same cpus that are used in smart tvs/smartphones).

The iPad Pro (a9x chip) is already stronger then the nvidia shield and completly mobile. Mobile performance is getting better by factor x2 every year. At this rate, we will see very, very soon ps4 like graphics on mobiles. Its probl already possible on the ipad pro (the device is capable of editing 3 4k video tracks at the same time with no problem).

Xbox Live or PSN arnt necessary for multiplayer. Ever played on a pc? There are first and third party solutions (uplay, steam, battlent, origin) and some games dont even need that. 

I dont see a problem using a controller on a smart tv in the future if they are capable on deliviering ps4 like power.

Easier said than done ... 

which game content on the ps4 or even on the ps3 wasnt possible on previous generations (like ps2)?

We already had big open worlds in GTA San andreas and Elder scrolls morrowind as an example.

The content is already the same. Only the graphics are improving.

no thats exaggereted.

Keep in mind bioshock mobile versions runs on iPhone 5 and above. So this versions only uses the iPhone 5´s power as an base.

The iPhone 6s is already ~10-20 times stronger then the iPhone 5. 

Check this gameplay of crysis 3 running nativly on nvidia shield. Thats an android tv box using an arm cpu (same cpus used in smartphones). The a9x cpu used in the ipad Pro is already stronger then this.

Oh okay got ya. Well of course anything can happen BUT smart TVs and smart phones replacing consoles....I can't see that happening. It is leaning more towards consoles becoming more as the center of entertainment in homes. For movies(DVD/Blurray), streaming movies/shows, gaming, social media etc. Multiplayer gaming just keep getting bigger and bigger esepecially online gaming. It seems more like Nin has become stagnant IMO which will hurt them in the long run.

They have some amazing games and franchises but they have been around since the dawn of video games almost. They really rarely if ever make any new games that take off. They always make high quality games don't get me wrong but those games are usually from established IPS that have been around for a while. Splatoon and Bayonetta 2 are the onnly ones that really come to mind that did okay recently. And while Splatoon sold well if I remember correctly Bayonetta didn't sell as well as expected to be such a high quality game.

Also while 3rd parties do carry a heavy load with MS/Sony they also give them mor efreedom to try new IPS and take chances. A liberty nintendo doesn't really have because they have like...no 3rd party games. I don't know....I guess I just can't see your scenario happening.