Jeff: I'm not sure the PGA Championship is in a position to "overtake" the U.S. Open anytime in the near future, unless the USGA keeps standing in their own way. However, I do agree with you on the PGA of America's marketing efforts at the event, compared to that of the USGA's at the U.S. Open.
I have attended three PGA Championships (2010 Whistling Straights, 2014 Valhalla and 2016 Baltusrol) and two U.S. Opens (2013 Merion and 2016 Oakmont), and each PGA Championship had a "bigger" feel to the event and site. The PGA Championship, while similar to that of the Open, has done a much better job with branding the event, in my honest opinion. And I say that knowing that too much branding could kill the event, but feel as though the PGA has done a better job with its balance (main entrance, corporate tents, grandstands, signage, etc.). And honestly, I expected the USGA to be better than the PGA in this arena.
Similarly, I felt that the crowd flow at PGA Championships have overall been better at PGA Championships than at U.S. Opens. In fact, I was pretty disappointed with the logistics at Oakmont seeing as how big the site was and how difficult it was to move around. I even found Merion easier to navigate than Oakmont, and that's a much smaller size.
Although I am a PGA member, I feel that I am being as objective as possible, and be sure that I am not one of those "I could do it better" type of guys. Just my honest observations.