I said it did it once, not that it hadn't. I knew Black Ops 3 sales were 15 milllion, but that was almost 3 years ago and hasn't come close since. I'll edit it to be more clear.

https://www.amazon.com/best-sellers-video-games/zgbs/videogames/ref=zg_bsar_tab_t_bs#3 
https://www.amazon.com/best-sellers-video-games/zgbs/videogames/ref=zg_bsar_tab_t_bs#1

If Amazon is anything to go by, then Mario should be winning in pre-orders.
The PS4 version of COD isn't even in the top 50 whereas Odyssey is currently in the top 5, and both games come out within a week of each other.

Granted, I think COD will have the bigger launch due to the much bigger install base,  the CoD audience already being there, and it'll be one of the heavily featured holiday bundles along with Gran Turismo and Star Wars.

Lifetime wise, I think it'll be much closer than people think, Call of Duty appears to be on a decline.
(VGChartz Data)
Black Ops 3: 12 weeks from release - PS4 + XBO - 1,077,340 preorders  All versions to date - 26.64 million
Infinite Warfare: 12 weeks from release - PS4 + XBO - 153,064 preorders All versions to date - 12.44 million
World War 2: 12 weeks from release - PS4 + XBO - 259,121 preorders                   

While WW2 should do and sell better than Infinite Warfare, it's not coming anywhere remotely close to Black Ops 3.

Meanwhile, there is a strong chance of Odyssey becoming the best selling 3D Mario game ever. With Galaxy 1 currently holding that title at 12.75 million. 
https://www.nintendo.co.jp/ir/en/finance/software/wii.html

So, based on this information, I'll say:
Pre-orders - Mario
Launch - Call of Duty
Lifetime - Wait and see

Well, I don't know about amazon......... we know that Ghost Recon Wildlands is still the best selling game this year, and splatoon hasn't even cracked the top 10 yet. Meanwhile amazon has splatoon 2 substantially above Wildlands. just throwing that out there.

anyways, my prediction:

pre order: cod

launch: cod

lifetime: odyssey

Tom Clancy came out on March 7th.
Splatoon 2 came out on July 21st.
That's a 4 and half month head start for Tom Clancy and how long has it been since that claim from Ubisoft, July 18th, 3 days before Splatoon came out, and those sales were as of June 30th, https://www.gamespot.com/articles/ghost-recon-wildlands-is-the-years-best-seller-so-/1100-6451779/

A lot can change in 3 months, if that best selling game claim is still true (which I doubt) and not even Breath of the Wild, Horizon, or Mario Kart, have topped it at this point, what makes you think Splatoon 2 would do it with significantly less time on the market than the first 3.
And Splatoon 2 DID crack the top 10. 
http://www.vgchartz.com/yearly/2017/Global/

And of course Splatoon 2 will be substantially above it ATM because its the latest big 1st party Switch title (Mario X Rabbids and Pokken aren't exactly at Splatoon's level) and will have substantial legs and will continue to sell throughout the Switch's life cycle unless Splatoon 3 is announced and released for it.
Meanwhile, Tom Clancy's sales are front loaded and comes out every year, cutting off its legs drastically, Rainbow Six: Siege being the exception.
Splatoon 2 will win in the end.

First off, yes I agree, splatoon 2 will outsell ghost recon wildlands when it's all said and done.

secondly, I was referring to the NPD numbers, not vgchartz numbers. Yes, I know npd is US only, but so are the amazon charts we are talking about, so it's fair game. Npd has Wildlands as #1 selling game as of the august npd numbers, and splatoon hasn't' even hit the top 10 there yet. At the same time, Amazon US has splatoon 2 much higher than wildlands in their yearly rankings.

my point was trying to show that amazon is sorta unreliable. My point wasn't to downplay splatoon 2's success, if that is what it came across as.