This is such a great thread and I agree with everything you said. But yes, I believe it is because of the PG era. WWE is a business now, back in those days they treated it as a wrestling world. Now it is all about money to the shareholders.
The PG era is so overly catered to kids that merchandise sales mean more than the quality of the product they are putting out. Back during the Attitude Era they had no choice but to put out the best product possible. Now that there is no competition anymore, they focus more on making money. Cena = merchandise sales with kids, CM Punk driving a Pepsi truck woudln't. Of course CM Punk driving a Pepsi truck into the arena would be classic (or anything similar to stuff we saw back in those days), but only to the real wrestling fans. The kids wouldn't appreciate that kind of thing, the kind of thing they would appreciate is Cena's spinning belt.
This is why TNA NEEEEEEDS to step up, boost their ratings, move back to the 9 - 11 timeslot and give WWE competition so once again they will have no choice but to put on a good quality product. But sadly, that is far from happening.