If Nintendo wants to win this fight they have to sell way more units in Europe and the rest of the PAL region. Because selling better Japan and the USA will only get the Switch so far. Since I doubt China is going to be a huge market for the Switch.

To add some context, the Switch isn't doing bad in the other regions (not US and Japan). When compared to the 3DS, the Switch is up life to date. Historically, Nintendo has not done well in Europe as the company never gained a foothold there (Sega did better in Europe, for instance). The DS actually did really well in Europe and other regions (it sold worse in the US IIRC). At the same time, the Switch may be like the DS and have a surge starting in the second year (which is possible as numerous Japanese third parties are pledging exclusives for the Switch and the system has been able to get a lot of software). 

As an aside, I would look at the number of games being released on the Switch. We are over 200 now (for a system that launched with 6-7). The second year will have a bigger pipeline

But we are not comparing the Switch to the 3DS (which will get outsold this year by the PS4) we are comparing the Switch with the PS4. As of now Switch sells decent in Europe,but the baseline needs to go to 65k in Europe to dominate the world market and beat the PS4. The Wii and the DS both did well in Europe and Nintendo needs numbers comparable to the Wii in Europe to actually beat the PS4 WW. The number of games (that matter for sales) released for Switch is still on the low side compared to the PS4. The line-up for PS4 games 2018 is very promising and third parties aren't very asleep either (except when it comes to Switch support). Now I am not saying Nintendo can't beat the PS4, although I give Sony the edge for now. But whether they will or not will for a huge part be decided by how well they do in Europe. 

well nintendo did announce 2 million sold, when they were at 2.3 million, but always looked at that as a mile stone.

The reason I compare it if that in their first full fiscal years, the PS4 and 3DS each shipped 14 million (3DS is to customers, but its irrelevant for this point). 

I don't think one region is a make or break. For instance, Sony does poorly in Japan compared to Nintendo's handhelds and the PS4 only has a 3 million lead over the XBox One in the US. Europe is Sony's major region for Sony, but Japan isn't. Conversely, Japan is a major region for Nintendo and not Sony. No one is saying Sony needs to dominate Japan in order to sell 100 million. Right now, the Switch is selling above the pace of the 3DS in "Other". SInce the Switch is projected to do as well as Sony did in it's first full fiscal year, I don't think the current European sales are that much of an issue. 

And of course, sales will likely improve in the next few years. I've made the comparisons to the DS because it followed a similar trajectory. It had a moderate first year and exploded in the second. The Switch is starting to get the pipeline of software it needs to do that.  Again, we don't know if that will happen, but the reports of Nintendo producing 25 million Switch units for 2018 speaks to that. 

Lots of disagreement in here but I think 1 thing we can all agree on - the PS4 will sell more than the Switch.

Depends, most likely but it isnt 100% yet. Many factors can happen

I think comparing consoles of the same gen and relative launch window is fair but not different eras since there's too many variables. As for why I'm here? I am here for the conversations. It's not easy to find good video game message boards anymore.

If they had the same kind of lifespan, I could see the Switch selling more. But, it's hard to think of a scenario in which that will happen. Sony tends to support their consoles longer in general, and Nintendo is launching 3.5ish year into the gen anyway.

If nintendo doesn't release a 3DS replacement and supports the Switch for a long time (with new models that have better battery life and are cheaper) then I could see the Switch outselling the PS4, assuming they eventually release a PS5. But that's a lot of ifs, so I'll stick with PS4.