He *has* held on to the belt for far too long. No doubt. His popularity goes up and down like the tides.
I definitely notice the back-and-forth chants. Summerslam, it happened again. But if you look at the merch numbers, Cena is outselling most of the RAW roster. And they won't/can't take the belt off of him until they design a new one -- spinner belts don't really work with anybody besides Cena. It looked dumb on Edge.
EDIT: I'm gonna close this since SS is over.. but sticky the "Does Anybody Here Watch Wrestling?" thread as the general wrestling discussion thread. Please continue in there.