It's not entirely true they didn't put out any Zelda games for the WiiU, just not any "flagship titles that were WiiU exclusives." They rereleased The Wind Waker and Twilight Princess. Hyrule Warriors was a WiiU Zelda title but it wasn't a flagship action RPG title, it was a hack and slash.

(I also believe that Breath of the Wild was originally developed for the WiiU)