Wow, I'm shocked, another "Nintendo should be third party", "Nintendo should be bought by Pepsi", "Nintendo should be a scissors company", etc. thread...

If you don't like Nintendo and desperately want them to leave the console business, then sure, it would be a great idea.

Nintendo could accept a deal with Apple or Google or Facebook or probably a half dozen other companies to make a console/portable with them rather than going 3rd party and still remain independent.

Sony/MS want no part of competing against an Apple console with Nintendo exclusives if it came to that. 

What does that even mean? So Sony and MS would just leave the industry if that happened?

It means exactly that, they would want no part in competing against such a massive force. 

Nintendo has lots of options, many companies would love to work with them. 

Every one of Apple, Google, Disney, Facebook, Samsung would likely be quite interested in working with Nintendo on top of just MS and Sony. 

You cant chose who you want to compete against if you are making a console. People wont stop loving Uncharted, Halo, Gears, GOW etc just because Apple and Nintendo released a console together.

No, but every major third party on the planet would support it 100%, and it would marketed out the wazoo and it would be more than a formidable competitor. 

Apple's marketing machine wipes its ass with the likes of Sony and Microsoft, Apple's in the big leagues. 

Why does Nintendo need to be brought?

Then why arent every third party in the world making many games for the Iphone only?

How'd Windows Phone go again? Or Zune? 

Microsoft gets by because they've had an OS monopoly since the 90s and businesses are kinda tied down to that OS, they've mostly failed miserably any time they've tried to market/compete directly with Apple on smart devices.