My point was how motion controls have changed how immersive VR is today.  When the person I was responding to retorted that a small percentage of PS4 owners have PSVR, I countered that there are more VR devices that utilize this than just PSVR, like the Oculus Rift with Touch controllers.  

Ow I see, I thought you were talking more on the size of the userbase than on the number of VR that use some form of motion control (I believe they all use)

And I disagree with this comparison. Microsoft's primary reason for making Kinect optional early on was because it drove up the cost of the system to $100 more than it's close competitor (and $100 more than the standard new console price), that was not only more powerful than XBO, but pre order numbers were running circles around Xbox One, partially due to the price difference (same reason many PS2 owners jumped ship to X360 last generation), and of course also the DRM fiasco.
Furthermore, Xbox One wasn't named Kinectbox One. So they could remove it without affecting the branding of the system. If you remove the 3D feature from 3DS, I don't imagine they would keep the name. Although I don't think this would be a huge problem. Just a sidenote.

3DS never really had a serious competitor, so Nintendo were less pressured to make drastic changes like Microsoft. They were able to lower the price of the system early on without making the feature optional. Microsoft were not as fortunate.

I don't know the percentage of 3D use, but based on polls it appears quite common that people keep it off.
And in terms of sales, New 2DS appears to be selling a lot better than New 3DS weekly in Japan.

Last week 2DSLL sold 47,230 in Japan. While 3DSLL sold 15,158 units.
http://gamrconnect.vgchartz.com/thread.php?id=234101&page=1

That's more than a 3:1 ratio. And the week before that it was a 2:1 ratio.
But there are apparently enough people that enjoy the 3D feature that Nintendo can comfortably keep it around. Kinect may or may not have been less popular. We'll never know for sure thanks to Microsoft keeping their numbers a secret. But they did discontinue making them, and that would suggest it wasn't popular enough compared to what it cost them to keep making them and supporting it with games. Because making games that support Kinect features is a more complicated and costly endeavor than just having a simple 3D feature for 3DS games.

And to people who don't mind a much more clumsy unfoldable version, when it comes to the standard 2DS model.
That monstrosity is not really an alternative for those who enjoy the form factor of 3DS, but don't care for the 3D feature.
They did however recently make a New 2DS, and that one works fine as an alternative. Which may explain why it appears to be selling a lot better than the 3DS. If it was available back when I bought my 3DS XL, I would have chosen New 2DS instead and saved $50.

No worries.  A poster had suggested that 3D in games is as worthless as motion controls.  I was pointing out how much of an impact motion controls have had on VR immersion and it spiraled from there.

Yes, the cheaper 2DS XL does outsell the 3D model now, but the 3DS still sells a significant # of units per week.  If "nobody" uses the 3D slider, why is anyone buying the more expensive 3D version?  That the 3D version still moves thousands of units per week, 6 years after launch, and even after the release of the 2D models, shows that yes people still do buy it for the 3D feature.

The PS4 had sold 73 million units and the last we saw, 2 million PS VR units have sold. That's a 2.7% ratio. 

 Sega CD had a 7.8% ratio. Let that shit sink in.

Is there any info how the regular 2DS sells in comparison to the other two? Just curious

I think the 3DS in its own right was profitable for Nintendo after the first few years, otherwise it wouldn't still be on the market 6-7 years later. Other things IMO were contributing to Nintendo's losses after fy 2014. Having to develop a brand new system so quickly after a failing one (Wii U), Nintendo has never had to do that before. I'd imagine development costs for Switch's 4 juggernaut launch year titles would've drained them as well. 

Though I do think 3DS somehow contributed to Wii U's eventual failure. Nintendo pumped so much money into saving 3DS that they probably weren't willing to do the same all over again for Wii U. They kinda just hung it out to dry it seems. 

First, I did make a mistake in my first post. Nintendo saw losses in 2011 and 2013, and they only profited in 2012 due to exchange rates. That said, the other three years were very meager. Even compared to the Gamecube days, Nintendo was making less money. For comparison, Nintendo's Operating profit ratio (operating profit to sales) was around 20% in the Gamecube days. In the last three years of the 3DS/Wii U, it was around 4-6%.

The reason Nintendo wouldn't stop the 3DS is because the hardware industry is one where you have to make your bed and lie in it. Consoles take years to design and then promote and manufacture. Nintendo could not just flip a light switch and have the system ready. Switch took a minimum of two years (as Iwata told us it existed as late as Early 2015). If you want a good example of what Nintendo thinks of the 3DS's legacy, notice how none of the features of the Wii U or 3DS carried over to the Switch. Even think like the Virtual Console, a Wii era idea, are dead. Nintendo is destroying their legacy and only keeps the system around to prevent a sales crash. 

The reason Nintendo was gung ho about saving the 3DS but not the Wii U is because the handheld market is more important to them. They can afford to lose the home console race by comparison. The Wii U's life was so short because Nintendo is replacing home consoles with handhelds. The Switch released in the 3DS's 6th year.