Re: when did WWE "JUMP THE SHARK"?
Rock "burying" Cena is debateable. Consider the fact that before hand, Cena had defeated everybody. So him losing earned his character more believability and thus more breathing room.
I'm not sure where WWE jumped the shark but I'd say it can be traced to the beginning of the PG era, guest hosts, etc. Not to say PG is bad, but WWE seems clueless about how to handle it.