3DS was a highly successful machine and 3D basically comes for free. People don't use it.

3D TVs are pretty much the same price as regular, yet people still don't buy them which is why they are going away.

The mass consumer won't buy it unless its part of the regular product, requires zero effort to use and doesn't have any negative side-effect (3DS narrow view angle and batter consumption). Not to mention devs have to want to put in the additional cost which increases their costs.

I firmly believe Nintendo won't put out a SwitchVR as they'll see how it has died off in mobile and other gaming world.

Metroid, a franchise with decades of proof as having limited appeal somehow being a killer app? Doubtful.
Nintendo getting back into VR, currently a red water market, competing with the existing companies over what has already been proven to be a very small market niche with declining size?

I don't see either happening. This is incredibly unlikely.

Nintendo and Apple aren't successful because they can magically make things popular, they're successful because they find and establish themselves in blue ocean environments. VR is not a blue ocean market, it's a small and shrinking red lake.

I think the OP is a lot of wishful thinking. VR, wont catch on because it takes you out of the real world. It's jarring and would only appeal to the most dedicated consumers. This is why it can never get off the ground and was smart for Nintendo to avoid it. Augmented Reality, on the other hand, has a lot more potential.

Where did you get the idea it's shrinking? VR/AR is underperforming sure, but it's still a growing market. China might become the driving force in mainstream VR adoption, yet mostly cell phone based. The market for $500 to $800 peripherals was always going to be small. Cell phone solutions launched prematurely yet with inside out tracking looking promising it shouldn't take too long before cellphones can handle full VR.

Anyway I'm looking at a rift+rouch add right at the top of this page, $550 now. Prices will come down, gen 2 devices will improve on everything, cheap standalone devices are coming next year, cell phone solutions are getting positional tracking. It's a bit early to declare it dead. It took 2 gens to get 3D games to work properly on consoles, PSVR hasn't even been out for a year...

Just published:
https://uploadvr.com/europes-vr-sector-grown-nearly-487-companies/
Still growing.

Vr for switch is unrealistic. The hardware does not have the necessary pixel density.

Your source doesn't say anything about market growth.

But there's no where near as much enthusiasm or interest in VR as there was just last year. I'd say clearance by 2019.

Also, if it is somehow big in China, it doesn't really effect the rest of the world. Canned air is popular in China, I don't think that speaks anything about how it's going to do on the Western European market. Let alone a product that's only hypothetically popular in China.

http://theknow.roosterteeth.com/episode/the-know-game-news-season-1-vr-is-d-e-a-d

A Tegra X2 or X3 based Switch that would have double to power of a current Switch with a 1080p screen could certainly work quite well for VR.

IMO, Nintendo started working on VR for the Universal Studios attractions and they in that process started to realize they could do some amazing things with the tech. You notice over the past year or so their tone on VR has shifted from "never" to "ok, we're researching", so something has changed.

Which doesn't surprise me because anyone who really tries VR can see "wow, it would be interesting to see Nintendo do something with this". Sure there are issues with VR, but part & parcel that's also where Nintendo's approach can may be very valuable in streamlining certain things and making the general experience more user friendly.

https://www.youtube.com/watch?v=NQHUomtWDxI
This could easily be on switch. At least on a next revision...

I'd hope that Metroid Prime 4 isn't VR-exclusive.