Its just the simple fact that Wrestling isn't considered "cool" at the moment. Doesn't help matter that the WWE doesn't have a damn clue on how to build or treat stars either. Everybody that they have potential to build as a longtime antagonist to Cena loses within the first matchup and its on to the next feud. When he has a great antagonist like Edge or Punk, He's at the top of his game.
The PG shyt is harnessing creativity. Think of how wild the Ambrose/Wyatt feud would have been in the Attitude/Ruthless era. Instead of this ring around the rosey shyt they doing.
He's at top of his game when certain guys are around? That's called being political and phoning it in..we say that over and over and over again with Kevin Nash in WCW and Cripple H in 2003.