With Mario Odysee, SSBU, the Pokemons, Animal Crossing and BotW 2, I am sure it would have broken 20 millions.
And these mentioned games would have looked nearly identical on the WiiU.
Odyssey - I'll give you that
SSBU - This wouldn't be on the Wii U. Wii U already got a Smash. At best, it would be more DLC characters. A six-year old game not named Grand Theft Auto V isn't propelling the Wii U to double its current totals and add a couple of million sales on top of it, even with Banjo & Kazooie and Joker thrown in there later.
The Pokemons - They would be on 3DS; let's not argue this either. There has never been a mainline Pokemon game on a console prior to the Switch, and the Let's Gos and SnS are only on Switch because where else is Game Freak going to put them? If the Switch releases in 2019 or 2020, then they are either on the 3DS or Switch. Zero chance of being on Wii U.
Animal Crossing - If the Switch releases in 2019 or 2020, then it's on the Switch. Zero chance of being on Wii U.
BotW 2- Doesn't exist yet. And when it does, it either gets released on the Switch and Wii U at the same time, or not the Wii U at all.
So if the Switch doesn't release until last year or this year, the only title out of all these that Wii U gets is Odyssey, and probably shares BotW 2 with the Switch at best.Going by VGChartz numbers, Wii U is just under 14 million. Let's say other Switch exclusives that Nintendo funded, such as Daemon X Machina, Xenoblade 2 and Astral Chain all release on the Wii U, along with things like Mario + Rabbids and the most compelling version of Starlink, due to having Star Fox. Remember that any game that has a version on Wii U already can't be counted for Switch, like MK8, Mario Tennis and Mario Party.
Do you think SMO, Daemon X Machina, Xenoblade 2, Astral Chain, M+R and any other exclusive Switch game that I'm forgetting (and Nintendo either published, moneyhatted, or allowed it's characters to be in) is enough to double its current sales? I'll also give you Marvel Ultimate Alliance 3, because I think Nintendo moneyhatted that one if I remember correctly. I'll also give you Travis Strikes Again: NMH, just because.
I'd also argue that certain ports such as the Crash/Spyro trilogies, the Disgaeas, Katamari, L.A. Noire, Rocket League, the South Parks, Valkyria Chronicles, The Witcher, Shining Resonance Refrain, Ys VIII and the ones I mentioned in my last post would not exist on Wii U. Most of those games were around well into the Wii U's life and were never even considered for a port, so there is no reason to believe they suddenly would be greenlit later on down the road, when publishers were long convinced that any Wii U port would bomb.
Wii U is just under 14 million. Would the games I mentioned two paragraphs ago be able to double those sales? I highly doubt it.