Because now we have to wait an additional 6-12 months before seeing Cain or Werdum have fights we want to see.
Over 88% of us rather see them fight someone else.
http://forums.sherdog.com/forums/f2/do-you-want-see-werdum-vs-cain-ii-3048473/
But you're still going to watch, so it's not a waste of time.
According to the UFC this is there ultima card
Maynard and Frankie Edgar III
Petis and Benson Henderson III
Benson Henderson and Frankie Edgar III
Silva and Franklin III
Miesha and Rousey III
Arlovski and Silva 7
Rampage and Wanderlei IV