It was pretty obvious that it was a special case, but nice to get it confirmed.
The Wii U tanked. Even as arrogant as Nintendo is, I'm pretty sure after the end of the calendar year of 2014, they knew it had become a large liability. Mario Kart 8 and Super Smash Bros for Wii U weren't enough to turn it around. The 3DS was successful, but far below the DS, below the Game Boy Advance, and below the Game Boy/Game Boy Color.
With all that in mind, they wanted to assure the world that they weren't sticking with the Wii U through 2017 and 2018. I doubt announcing the NX as a mystery platform (home console? hybrid?) had much of an impact on Wii U sales.
Lifetime Sales Predictions
Switch: 151 million (was 73, then 96, then 113 million, then 125 million, then 144 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 57 million (was 60 million, then 67 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
