How much Nintendo paid them? There is nothing exciting about Switch compared to Wii U. All of them can easily make their games for Wii U right now:
Portable aspect? Off-TV play on Wii U.
Detachable Joy-Cons? Wiimotes.
Mario Kart 8 and Splatoon? Just upgrades existing Wii U versions with new content.
Skyrim? It easily can run on Wii U too.
Wii U also have advantages with additional touch-screen controller. Switch have, well.. puppy-head? Nothing, but cute.