It would have to be a different chip that would require all games to be ported over which would take a while and many devs would not bother. 

Nvidia would just give Nintendo an equal or better chip and Sony is back to square one. Are they willing to make new games and new entries of major franchises? Are they willing to put Uncharted 5 on Vita 2 first and foremost?

If the answer is no, then they can't compete with Nintendo, because Nintendo puts 100% into their portables, Sony does not. 

I think by the way there will be a Switch Pro or higher end Switch by 2020 if not sooner. Current Switch will get a die shrink to 14/16nm and aimed more for younger audiences with a cheaper price point. Nintendo will not allow Sony to have an advantage here, this is their primary hardware line if anyone is coming to compete directly they better be ready for a fight. 

Awesome. Care to tell me about a mobile version of an X86 APU that's supposed to reach PS4 levels of performance while maintaining a 3+ hour battery life by 2018-2019? Because that's what you'll need to do what you want to do.

Do what they have been doing... Exclusive after Exclusive, with something Switch may not hold onto AAA 3rd party games.

Sony is sony, nintendo is nintendo they dont even need to counter or compete.. but what i would love to see is a merger but i know that will never happen

I don't think that term means what you think it does.

Not to mention it doesn't even apply anymore, but what is the truth if not a detail, huh.

The best case 3 years from now would be a "7" nm chip from GloFo or TSMC which is about ~3-3.6 times as efficient as the Switch hardware.

Even then, you would be halfway to the computing power of the Xbox One.

As many have said here, the tech just isn't there yet for an affordable price. People talk about $300 for a Switch brig expensive, imagine a PS4-like Switch..I wouldn't even think about affording one for years until it can go down in price. Then all this exclusivity thing is kinda debatable. Yes Sony has western AAA third party exclusives, but Nintendo's first party exclusives are hard to match, especially if you add in Mario and Pokemon to Switch, two of the biggest juggernauts in gaming to this day. And if the Vita is something to go by, I'm not sure if western third parties will exactly be on board since they're used to the home console front so that advantage can be neutralized.

Let Sony and Nintendo do their respective thing. They're making money now so something's going right for them.

I think there will be mobile chips about on par with a XBox One in 3 years yes ... the problem for Sony is Nintendo has access to the same or better tech as they would and this time around IMO Nintendo would not give them much of a hardware advantage.

Tegra X1 for Nintendo is still relatively high end, it's a 2015 chip in a 2017 product, though really lets be honest Switch was intended for fall 2016, it just didn't make it because of software delays.

IMO this time if Sony wants to step up, they are going to find Nintendo will not retreat. This is Nintendo's hardware ground, they will fight Sony tooth and nail for it if need be. 

Plus future Switch iterations would be backwards compatible with all old Switch software, so there could be hundreds of titles available for Switch by the time Sony shows up to this party, they are going to be way behind and have to deal with the formidable presence of Nintendo's entire 1st/2nd party might. 

I would say there is no way Sony will do a portable PS4 at all. Digital is bigger now because many games are being released as digital only, so it kinda has to be bigger. Still not sure a digital only device will sell well. Unless they also make it double as a smart device and the games cost 1-5$...

There's just no room for Sony.

Mobile kills them on one end, and then they would have to go toe to toe against Nintendo, who doesn't like to fight, but if you push them .... you are going to have a fight on your hands.

There just isn't room for another device. It's a semi-miracle the Switch is doing as well as it is given the conditions, but Nintendo always had a strong foundation to work from as the 3DS was still reasonably successful.

Besides, they can't half ass it, they have to focus on it fully, and if they do that, Playstation 5 will suffer and Microsoft will be all too happy to take advantage, and then they're going to have to scramble, and so on and so on.

OK, here is My exciting idea! Sony branded crack!! Nintendo won't stand a chance at that point!
Wow! Magic!