It is definitely possible that Nintendo, after playing with VR and loosely planning the strategy, regroup and postpone it. They are doing that quite a bit lately being careful not to share what isn’t certain, but they would be missing a nice window. I also think you cross another good point that Nintendo’s handheld tech is progressing nicely and the next full generation should be almost negligible difference with that gens abilities, however even if that is the case, strategically, they would only be on similar ground with Sony and MS, which has shown in the GCN/PS2/Xbox days not to be the best situation. I would be worried for that outcome even if Nintendo did have portability on its side. 

I think with Switch being a “sectional” console, the opportunity is there to extend it’s lifespan with upgraded “parts” in a way that no console has done before. If they maintain the joycon setup, then they could just upgrade the body for 2 generations with a flexible enough design surrounding the components. The Switch life could even span 7-10 years.Their marketing is nearly spot on right now, but, again strategically, if they do not fully utilize this window leading up to the next gen, then their rise may be shortlived. To keep hype propelling, they need to ensure more leaps in design and wow experiences like BoTW offered. They are on top of things this gen, firing on all cylinders. I know they know these things and more and are comsidering the options. We cannot assume that these steps are going to be ordinary and expected. Timing is critical, and Nintendo has shown that they are definitely playing this game. They have to. By combining the handheld and home console markets with Switch, one wrong move, false industry-read, or ill-timed release and they could be all but done. It’s what makes the game industry so interesting to watch.

Nvidia has some impressive VR tech that Nintendo could use.

https://www.pcworld.com/article/2926083/nvidias-radical-multi-resolution-shading-tech-could-help-vr-reach-the-masses.html

“It’s between 50 percent and 100 percent less pixel work [compared to traditionally rendered VR scenes],” says Peterson.

That’s insane. Even more insane: The reduced quality edge regions truly aren’t noticeable in the final image unless the compression quality is cranked to extreme levels.

I could see some kind of VR addon/support for Switch, but we want see 4k with this Switch (maybe with Switch 2), Tegra X2 don't have near power needed for 4k (Switch with Tegra X2 would be Switch Pro not Switch 2).

Tegra X2 is old news, Nvidia likely already has something beyond a Tegra X2. 

Also look at the link of the VR tech Nvidia has which dramatically reduces pixel rendering for VR games, you can cut the rendering load by half with minimal reduction in image quality. 

Ofcourse its old news, but fact that Nvidia has something beyond Tegra X2 doesn't meant that Nintendo will use it near future, best bet is that Nintendo will use Tegra X2 in Switch revisions for next year.

I said that we could see some kind of VR addon/support for Switch, but hardly we will see 4K support in near future.

This sounds a lot of like the rumor SuperMetalDave has been floating around that is full on BS. That dude has been so salty since the Switch reveal. Nothing he predicts ever comes true.

Switch VR

- 1080p display (cheap but high quality enough for decent VR).
- System is somewhere between 2x-3x a current Switch (new custom 7-10nm Nvidia Tegra Mariko)
- 8GB RAM
- Comes with light weight, user friendly plastic face mask, designed by Nintendo for comfort. Can "switch" to augmented reality. Built-in gyro sensors and earphones for "HD Sound".
- Switch VR features new VR Joycons, tailored more to the VR experience (sensory feedback)
- No complicated setup or cables.
- $399.99 US

Software: Metroid Prime 4 (launch title), Luigi's Mansion 3 (optional), Mario Kart 9 (optional), Splatoon 2 VR DLC pack, ARMS 2, new Nintendo IP using VR.

Can play all existing Switch software and can be used as a regular Switch outside of VR applications. Summer 2020 release date.

$399.99 for Switch VR
$199.99 for regular Switch

I actually think that would work really well.

Nintendo now has a great relationship with Nvidia. It isn’t unlikely that they develop a deal to create a graphics chip that is built off the same architecture as the Tegra for Switch family compatibility yet have specific accommodations for behind the scenes advances in VR. We do not know the full interworkings of their relationship and communication, but evidence suggests that technology is close to prime for such a custom situation to be made in the next 1-2 years. With the Switch, technology and situations had to be just right for for use of the Tegra chip, flash card sizes and prices, battery life, usb c, size of components, software compression, price of everything, etc. Nintendo in their many handware developments is well versed in manipulating existing technology situations to their benefit.

Funny, before Switch, just because Nintendo hardware was less powerful, everyone assumed they sucked at hardware and should stop making consoles. But they know more about making diverse gaming hardware and industry timing than any company at this point. I’m not saying they are flawless and have definitely made me wonder sometimes, but they know what they are doing.

While i am sure they are going to upgrade Switch at some point i expect it will be something like DSi or New 3DS, a little bit more powerful and some new features that won't fundamentally change the experience. Upgrading Switch to such a degree that that it can do 4K and VR can only fracture the userbase

There was also that "leak" for a new Tegra Nvidia chip codenamed "Mariko" for Nintendo that had 8GB of RAM. Who knows, maybe all this is connected. Some people speculated Mariko was for a Switch revision to halt hacking/home brew, but newer Switch models are already out which fix that issue but they aren't using this supposed Mariko SoC. It must be for something else. 

https://wccftech.com/nintendo-switch-hardware-refresh/