Even in that sceario (the doom sayers want to entertain so lets, shall we), Nintendo is not freaking Sega. They have ample cash reserves and their handheld business will be a revenue stream for the next 6-7 years even if smart devices continue to chip away at that market. 

They would never grovel like Sega and become a common third party. 

Microsoft and Sony would have to line up and court them. And they would likely only work with one or the other. Nintendo has all the control here because they are effectively the "king maker" in the game business in this position -- who ever the allign with basically the scales of the console war would tip in their favor. 

For starters, if it was Sony, Sony would likely have to give up their handheld business period or simply cede it to Nintendo. So there's that. If it's Microsoft, they would have to offer Nintendo some kind of proposition with Windows Phones I would think. 

Third Nintendo would have to be getting a metric ton of money to make up for the royalties they used to make on their own unique console. 

Nintendo could also get marketing kick backs (Sony or MS agree to pick up the tab for all of Nintendo's TV marketing for example) and they could also insist on input on any future hardware and perhaps even co-branding. 

Personally I think Microsoft would bite and meet Nintendo's terms, leaving Sony out as a loser in the console biz. Mario + Halo + Titanfall + Zelda + all third party support + Gears + DKC + Killer Instinct + Rare returning = game over for Sony. Vice versa if Sony could get them on their side, it would be a similar result, gave over for Microsoft. 

So strictly put, in this scenario ... MS/Sony fans shouldn't huff and puff so much -- Nintendo is the one holding all the cards. 

what's wrong with this site today?

A wild console appreared.

It seems to have been contaminated by the PS4 launch.

Didn't Nintendo confirm this years ago?

Also, grovel like Sega? As much as that means my personal favorite games will most likely never see the light of day again, instead favoring insipid Sonic cash-ins, nothing wrong with that approach from a business standpoint, why offer software on a single cash-hemorrhaging platform at a time when they have 5-6 viable platforms to work with?

Nintendo collaborating with Microsoft isn't magically going to restore Rare to their former glory either. Stahp.

Is it one of those "alternate time-line" comics, like the one where mutants took over North America?

You said it yourself, they have loads of cash. They more then likely already have a new console in RD. I highly doubt they will just call it quits after wiiU no matter how much it ends up selling.

Those threads were just hypothetical if you're replying to them. I don't think they were meant to be doom threads, just something to think about. You could have made the same kind of thread about Microsoft and Sony.

I think this is one of those "If Germany Won WWII" sort of deals.

It's a hypothetical future if Nintendo opts to not make more home consoles after Wii U and just work on handhelds, they are certainly not in the same position Sega is in.

Sega would be the equivalent of a 40 year old former prom queen who's got 2 kids and isn't getting alimony from her deadbeat ex, Nintendo's still a Victoria Secret model, just because she broke up with her boyfriend doesn't mean Joe Schmo at the nightclub has a chance ;). She would have movie stars and rich big wigs lining up to wine and dine her. 

If either Sony or MS wanted Nintendo games on their console they would have to offer up *a lot* and probably cede some control to Nintendo in the process.