Didn't the Wii end up selling quite a bit more than the Gamecube? What is it you don't understand? I'm saying that Switch will sell more than the Wii U but also that current Switch sales are most likely Wii U owners upgrading, by simple reading the available data. Besides; the Wii version actually launched one week before the GC version and during the best selling weeks of the holiday, so it's impossible to compare. Switch will sell more than the Wii U for sure, but we have nothing that indicates that it will sell anywhere near as much as the Wii, like some are claiming already.

If 80% of customers buy Zelda for Switch, despite the Wii U's obvious advantage, that means that most customers prefer Zelda Switch. Are you telling me that the most anticipated Wii U game of them all has disappeared off of Wii U owners' radars or would you agree that it seem that a whole lot of Wii U fans have decided to pick up a Switch with Zelda instead? It makes perfect, it's actually the only scenario that makes sense, there's no reason for the Wii U version to be doing this poorly otherwise.

And since this is the most likely, it also means that we can't jump the gun and go crazy over the Switch launch numbers, since it's exceedingly likely that the majority of sales were simply pre-orders made by existing Wii U owners and as such it offers no insight into future prospects. Heck; the Wii U had a really good launch, and even the first Xbox and Dreamcast did, the first few weeks tells us very little, and it appears that it isn't sold out either, unlike the Wii was for nearly two years running.

My main point is simple; current data suggests that Switch is a hit among Wii U owners, but there is little clear indication that it will be a big hit outside of these circles. The impending death of the 3DS will add some sales for sure, but quite a few users are talking about this as a new Wii, which is quite ridiculous if one compares the factors of the respective launches and products, as well as the competition and conditions of the overall market and Nintendo's current and ongoing position in it (or lack thereof).

Given, but I think PS4 is a bad point of comparison. Switch is a handheld and should be compared to 3DS (which sold better initially). Nethertheless, first hurdle taken, launch is fine. Now onto sustained momentum, we will see if that happens in the next two or three months.

Switch is a succesor to both the 3DS and the Wii U.  So it needs to be compared to them both combined. And it's not beating their combined launches anywhere.  Basically Nintendo's market share is going to decrease compared to last gen if this is really succeeding both handheld and home. 

Ah, OK, I understand now. I agree with your assesment. And it is pretty clear, that launch-numbers are no indication of sustained momentum, all they say that the launch wasn't botched. So while a short celebration about good launch is in order, we should keep in mind that failures like WiiU launched in similar numbers. The post-launch-momentum is what brings in the big sales. We'll see how that goes.

Well, it's not beating 3DS alone, so not combined.

I'm not sure combined works though. I owned both WiiU and 3DS. To be exact, I owned over the the time 4 3DS. I doubt I'll own 5 Switches. So I don't buy into the argument it should make the combined numbers. It replaces both WiiU and 3DS, so I need only half as much devices.

I think we need a new baseline for hybrids.

Oh yeah you're definitely right.  Many Nintendo fans in the past had multiple handhelds over the same gen thus inflating the sales.  I've 2 younger sisters and they went through something like 6 DS's between them because they kept on breaking them.  

So we need to consider the handicap that Switch probably won't be bought multiple times by the same fans.  So maybe Switch vs (3DS + Wii U) and we subtract 30% of the 3DS sales?

I'd like to add one more significant potential factor; consumers who never bought a Wii U due to pricing or not being a fan of the concept itself. This could be a decent chunk of customers when all is said and done and I think that quite a few sales, especially in Europe, can also be attributed to consumers who have been waiting for something from Nintendo they really like.

I'm one such customer, and after having played the Switch myself in docked mode and tried one of the best games ever made on it, I can safely say that I'm eager to buy one of my own when the price goes down somewhat, launch hick-up's are fixed and the library more expansive (I typically wait at least one year with new consoles). I have no interest in the portable aspect but it works well enough as a home console.

I'm still not convinced it'll be a mass market hit though or that 3rd parties will put in a real effort, but among nerds it seems quite popular and will probably remain so, and we can't be unerestimated!