Yeah, with stock issues still biting more than three months after launch, I think Splatoon 2's impact is going to be dampened somewhat by a lack of available hardware.

It's certainly possible. The Switch will have sold around 4.3m WW when ARMS launches barring glaring stock issues (this was calculated with a 150k global baseline and a stock boost for ARMS).
If Nintendo can maintain that it should be around 5m when Splatoon 2 launches. That is a big enough install base for a juggernout franchise to achieve 2m at launch, but I think the deciding factor will be japan (as well as stock).

Seeing how well it's tracking on COMG, Amazon.jp and Rakuten it might do 1m or close to that on launch in japan alone. 1m for EU+US+RoW should be achievable for a big game launch.
MK8D did 1.2 WW for launch, with around 300k of that coming from japan. That puts the rest around 900k and this was for a port, not a brand new game like Splatoon 2.

In short 2m launch is feasable. The remaining 2.7m legs within this year is where things get tricky, because they depend so much on Nintendo providing enough supply, especially in japan where the game will probably have it's best legs.

Well, since Nintendo announced 3.6m for Splatoon 2, I guess this prediction will turn out to be true, won't it? It just needs to sell 1.2m this quarter (holidays) to match the first Splatoon.

Just looking at the first pages, it looked like most people doubted it, but the poll says otherwise. Weird. xD

Congrats Lipe, this was a bold prediction and you are on pace to win it.

Nicely done. This reminds me of that time when people thought Xenoblade X would outsell the OG Splatoon. The squid just keeps getting bigger and bigger, it seems.

Thanks. ^^ It seems Splatoon is a game that never ceases to surprise us!

Nice.

It's possible,but it also is,indeed,a really bold prediction.There's too much games in november for splatoon to compete with.

Breath of the wild is at that number right now, counting Swtich only. Wii U version is another 1.1+ million on top. So looks like Zelda did it.

Well, Zelda might have outsold Splatoon 1 in its frist 6 months.  I mean its at basically 6 million right now and its been what 7 months, or is it 8?

Software Numbers:

BotW: 4.70M
Mk8DX: 4.42M
Splatoon 2: 3.61M
1-2 Switch: 1.37M
ARMS: 1.35M

MK8DX easily got that 4 million. Looks like we will have 3 games that sell over the Splatoon 1 4.67 number. I Wonder what Mario Oddyssey will do by Jan 1 2018.

Odyssey at 2M in 3 days, so it will see a good boost during the holiday