The main problem for Nintendo was that countless Wii buyers never moved beyond Wii Sports and maybe Mario Kart. Despite having over 100 million units sold, staple franchises sold pretty badly compared to the Switch.
Smash Bros Brawl? 13 million sales. Smash Bros Ultimate? 35 million.
Animal Crossing City Folk? 3 million. Animal Crossing New Horizons? 47 million.
Mario Party 8? 9 million. Super Mario Party? 21 million.
Zelda Twilight Princess? 8 million. Zelda Breath of the Wild? 34 million.
Basically, the Switch has 50% more units in the world, but you can tack on 200%-400% more sales per franchise entry in general; and some extreme breakouts. For this reason alone, Nintendo is never returning to Wii-era gimmicks, and we’ll probably never see “Nintendo Selects” again.