I strongly believe Nintendo still has the craftsmanship to make their games relevant. I would argue the platformer-heavy Nintendo offering on the Wii U wasn't a good example of Nintendo's diverse libraries; no realistic sports (1080, Wave Race etc), no strong racers outside of MK - not even a "real" Mario (yes I will use that term) or a Zelda.
Marketing is also incredibly important in this day - I remember seeing Splatoon youtube adverts which I feel contributed to its great success. Sony and Microsoft dominate the bus posters, billboards and every other outlet for marketing - I can't even remember a Wii U game being advertised on a billboard.
IMO a game like Star Fox should be a launch title, not a game coming out three years later. A game like Paper Mario should be 'mid-gen', not as a swansong.
Im just trying to point out why the Wii U's performance might not be a true reflection on how appealing a Nintendo box/games are.