I guess it comes down to merchandise and outside exposure, Vince can care less what wrestling fans want, if he thinks Cena still has the pull to get media coverage and PR he will stay the face of the company.
Look at the Rock, he didn't win the belt because of his wrestling or history with the WWE or even for the fans cheering and wanting him back. He won it because of all the exposure he got from it, everyone reported it giving vince a ton of positive PR and giving Rock a spot to plug his crappy movie. He is worse than Cena in every way
Yup. It doesn't matter that Cena is booed by half the crowd, it matters that his face is on boxes of fruity pebbles.
I mean, for Pete's sake, photos hit the net of Cena with his girlfriend, and to keep him from looking bad (two-timing AJ), they immediately rewrite the whole storyline to turn HER heel.