It did at one point.
After the first delay they announced it was gonna now be for the new system and not wii u anymore.
Then when they officially announced BOW..they said it would be wii u too.
That's not what happened, the Wii U version was never cancelled. Nintendo just decided to develop a next gen version once they knew the Wii U wasn't going to be in their long term plans.
We've only seen Wii U footage of the game up until the Jimmy Fallon show 2 months ago. That was the first time we saw the Switch footage of the game.