1.User fatigue. Many people who  bought the PS4 early in its life will begin to see it as somewhat dated and the idea of replacement is more appealing. 
2. Power. The bigger a power leap they can demonstrate at an affordable price, the better the appeal of the system, both to gamers and developers alike. 

Then we should pressure Nintendo into doing so with the NX hardware.

because it wont be a direct competitor in 2018. it would be a new gen, a competition to ps5/xbox two. 

nope, never said it should launch 2017. So its logical.

Nonetheless, in 2017 it could already be strong enough to compete against an probl ps5 and be a real 9th gen console.

wii u failed in 2012 because it was just as strong as ps3/xbox360 which much bigger installed hardware bases.

If Wii U would be as strong as the ps4 in 2012 and x86 based (easy third party support), im sure it wouldnt fail.

Wow. I know it's your opinion, and I respect it, but you know all of that... how?

We now almost anything about the NX! As I see it, it could be the best Nintendo console ever, or the worst, or even an average console. Until we get some official information from Nintendo all we can do is speculate.

If they release the NX so "early" we're getting another wii? Well, that sucks, I bet Nintendo don't want that. Who would want to sell 100m of consoles? Crazy, right?

Also, how can you be so sure about all of those games missing at launch or missing at all? Have you seen Nintendo's output these past year? There have been some great games, but lots were cheap and quick games to fill the catalog. Are you seriously expecting Nintendo have been doing nothing for the NX all this time? Retro and ead 1 I think, have been working for two years on something, and some small games being filler indicate that they are indeed working on the NX. 

If I had to choose, I'll be the happiest man if they release NX platform in november 2016. If it's good and has good games and price people will buy it. Think about this, maybe people do the same as with the ps4, and 50m buy it "because my friend has bought it, so me too" xD

The only thing I agree with you is that maybe, just maybe, if they release it "too soon" it won't be what I'm expecting. I'd love it to have most of the leaked patents, specially that awesome free form controller, and it might be too soon for that (expensive, actually). But games? I'm sure they'll have plenty of games for the NX first year on the market.

At least that's what we should expect from them, to have learnt something from the wii u's failure.

But I'm optimistic. Merging handheld and console developing looks promising. I read somewhere that they release 18-24 games on average every year for both, now, if NX is really capable to play the same games in both, that would mean almost zero droughts. Everybody wins :P

It doesn't matter what hardware Wii U had as long as the games were just as bad as they were/are. I don't think this is a matter of 3rd party games, as Wii U did have somewhat moderate 3rd party support right out of the gate, but it dried out because that's what nobody was buying. Multiplatform games hadn't come earlier in any case as they did for the PS4/X1 anyway. 

They should be able to make something considerably more powerful than a PS4 this year or next year though. You don't need to wait until 2018.

AMD has 14nm/16nm Arctic Islands GPUs coming this year that will blow the PS4's GPU out of the water.

I'd say release a 3TFLOP-range high end console this fall and start building that userbase quick (having Zelda, Splatoon 2, and Mario 3D in the first 6-8 months will be critical).

Then in 2018 release a 4K NX model. 

NX is a platform, it's no single console or portable. Nintendo games just scale up and down, third parties have the choice (games can work on specific models depending on hardware need or all them if they want). 

Why adhere to "rules" if they only benefit Sony/MS. Change the rules, it's 2016, you don't have to keep making hardware like it's 1989 forever.