Give me compelling reasons/proofs why Wii sports or Wii Fit won't be huge system sellers again for WiiU

[Cobretti2]

Well simply put there is no reason to update.

It like a FIFA or a BASEBALL or a BAKETBALL game for me, I update very few years as the game play doesn't really change.

If a game was designed to provide you exercise then why upgrade when the original is still working?