I buy Nintendo systems for Nintendo games. I do buy a 3rd party game for Nintendo systems here and there. Nintendo Handhelds are a different story. I buy both 1st and 3rd party games in equal number.
I doesn't both me that Nintendo systems get less 3rd party support because I just buy 3rd party games on other systems.
When I buy a Wii U I can guarantee it will be for Mario, Zelda, or Metroid.