Agreed. 6 years tops. Easily 5 years.

Tell you some secret - the Wii U didn't sell at 199 EUR !! I've got mine - a WindWaker HD premium bundle - for that price. I was worried to no end as I saw this offer three weeks after it was advertised....

But - the local retailer had stapels of them!! Even on the day Donkey Kong Country Tropical Freeze was released...

People didn't buy for 199 EUR. Instead they were looking for 399 EUR PS4s...

You're right in that Nintendo is seen as a "toy maker". But there lies Nintendos strenght: they need to embrace this to the fullest potential. The GamePad enables creativity on the user side never seen before in games. 

So Nintendos challengers are not PS4 or XOne but the tablets. And Nintendo offers something here those devices can't: integrety and the good feeling that kids only see content suited to their age.

Nintendo sold a ton of DS via "Brain Training" to people who would never bought a DS otherwise.

Nintendo sold a ton of Wii via Wii Sports to people who would never bought a Wii otherwise.

 Nintendo know needs a Wii U title to sell Wii Us to families as neither PS4, XOne nor tablets are a real alternative.

the console will go till 2018,2017 earliest, i think it will have a 5-6 year lifespan

Yes, I do beleive we will see support until then, if not at least in the form of 2nd and 3rd party outsourcing of their I.P, in the manner of Hyrule Warriors type deals.

NES also has 2. Also, rom hack or not, Majora's Mask is a completly different game from Ocarina of Time aside from the graphics, and even feels better and different.

Edit: Also, NES+N64+GameCube (2 Zelda games per console) > SNES+Wii (1 Zelda game per console)

About Zelda 2, being different or "bad" (it is a very good Zelda game) it is still a Zelda and counts. And finally about Majora's Mask, again, they reused the same graphics because they needed to release soon, but still a different one.

The WiiU struggling after launch, even despite the price drop, was the consequence of bad marketing and a perceived sentiment of bad investment. At that time, now it is a better investment and sales prove it.

And finding the next "thing" is easier said than done. NintendoLand was supposed to be that game, or something close, and it failed. And I'm not sure if even Nintendo is trying to find it with WiiU or if they are already trying to find it with their next machine.

Problem is a lot of kids don't want a "kids console" for one. Once kids (especially boys) get to about age 9/10, they start to shun "mom approved" products, they want the console their older brother is playing. 

Also I think families are just fine with tablets, lets be honest just because Wii/DS started the "casual/family" play craze doesn't mean they were entitled to own it anymore than Blackberry is entitled to the smartphone market because they were making smartphones before other companies moved in and stole their thunder. 

To be honest, tablets/phones simply offer a better value proposition to casuals/families. The games are dirt cheap or even free, the interface is so easy to use that 3-year-old can master it (no buttons period, every human being understands the concept of touch with their fingers). So the whole "the traditional controller is a barrier" thing has long since been shattered by multiple devices. Beyond that Nintendo devices are laughably restrictive for most casuals, they don't do anything particularily well but play games, whereas a phone or tablet does 50 different things reasonably well. 

Nintendo just can't compete with that, not even factoring in that their marketing can't touch Apple's. People like Mario just fine, but they don't like Mario *so much* so that they will go that far out of their way to bend to Nintendo's idea of what family gaming should be. 

I can understand from a parent's POV too ... raising kids is damn expensive as is, if little Johnny is just as happy playing a $1 Clash of Clans or something versus a $40 copy of Animal Crossing and a seperate $200 purchase for a 3DS XL (versus a iPad that's already sitting around the house) on top of that $300-$400 console that you know you're going to have to buy too ... as a parent who has to pay for bills, braces, ballet class, hockey equipments, summer camp, etc. etc. etc. for his kids, that suits most parents just fine. 

Next year will be it's peak year. And then a solid 4th year and the 5th year will decline towards to launch of the next system at years end.

As long as it's 3 more I'm happy.