Let's make it a bit more fair and take a look at some other franchises:
GC: The Wind Waker, Twilight Princess
Wii: Skyward Sword
Wii U: Open world Zelda
GC: Metroid Prime 1/2
Wii: Metroid Prime 3, Other M
GC: Super Smash Bros. Melee
Wii: Super Smash Bros. Brawl
Wii U: Super Smash Bros. 4
GC: Star Fox Adventures
Wii: -
Wii U: Star Fox U
GC: F-Zero GX
Wii: -
GC: Super Mario Sunshine
Wii: Super Mario Galaxy 1/2
Wii U: Super Mario 3D World
While Super Mario Galaxy 1/2 were great games, I still enjoyed 3D World far more. So putting Super Mario Sunshine aside I'd say that Nintendo most definitely make superior games when hardware sales are low.
And for the record, Monkey Bike Wii is a piece of trash.







