Let's see them make a comeback first. And even if they do let's see if their system really competes with Sony and MS. Wii sold great but it barely affected the sales of ps360

If Nintendo gain support from third party then there next console will only be for casual (because they clearly will not make a powerful console anymore at this moment simply their market had been consumed by PS and Xbox brand) and not competing directly with PS4 and Xbox One, so the answer is it will hindrance the PS4 and Xbox One sales, but if will not affecting the entire sales and potential, just like how Tablet, like iOS and Android competing with consoles like PS4, Xbox and 3DS

they get more important for the sony/m$ 3do, but they got a lot weaker.
the major 3rd party ips are losing strengh every year, cod bf, asscreed,etc are declining and losing brand power with every new game.

and even fifa isnt growing as strong as the football market and is losing brand power.

I'm reading a lot of posts which go along the lines of "7th gen proves that wrong."

Well, yes and no.

Sony is making money hand over fist with the PS4. It's one of a very few product lines Sony is doing well in, and even if Sony as a whole goes bankrupt, they will not bow out of the console biz.

Microsoft, however, is in a much shadier position. XBox does break even or even makes a small bit of money, but because Microsoft reliably makes money with Windows and Office, it's one of Microsoft's weaker brands. Microsoft got very lucky last gen with Sony's inept PS3 launch. If they get sandwiched between a strong Nintendo and a strong Sony console, they will bow out.

Despite having a gaming PC too, it's not that simple. Some games have issues that need some tweaking before being playable, even with the patches. Dowright terrible ports are also a reasonable common issue. And we have more technical knowledge than the average joe. Even in our case, it's not that easy to determine which GPUs are equivalents, if GPU A beats GPU B, etc. And even the requirements aren't always reliable. I found Shadow of Mordor requirements to be exagerated, since the game is much less demanding than they said it is. Mortal Kombat X however seems to not be playable with the minimum requirements they informed (the port is also bad).

Choosing parts to build a PC isn't simple too. While I agree with your case with PS3 patches, PS4 does a way better job in doing things automatically. Installs take 2 minutes max, it downloads all the patches in the background automatically, it's basically pop the game in and it runs, while the console downloads any patch and does the job without any worries. Yes, I have bought digital copies on the consoles. All games worked fine, no issues. The store works.

What happens in your case is that you have the tech knowledge to deal with any issues. So it seems easy. A lot of people don't even know what a GPU is and they aren't able to even install a damn printer. These people are the reason why iPads sell a lot: they rather pay much more for less power if it doesn't piss them off.

This what? the wii didn't have the third party support the others got. If it had, wii would have sold much more and ps360 would have sold way less.

Actually, nintendo appeals to exactly the same people that buy ps and xbox while appealing to other people at the same time.

They need at least 2 new great M-rated series and Zelda needs to go Teen for a fresh setting.

Survived the Wii...So yeah.

Hmmmm. I personally think a more appropriate question for the home console market is, can Nintendo survive (in their current form) if they don't make a come back?