I guess we would agree that George Lucas' stuff in particular symbolizes that
Y'know, I actually wouldn't agree with this. The first film in the original trilogy was a fill-in-the-blanks of Joseph Campbell's monomyth, and the other two were mostly not Lucas' work. He had a whole bunch of people serving to keep him in check, whereas on the prequel trilogy he had a whole bunch of yes-men who wouldn't dare disagree with the Great George Lucas, praise be unto him.
It's not so much that Lucas has lost his creative flair, it's that he never had it, but the more power he has the more obvious it becomes. That said, I wonder if this might be at least in part the case with FF7 compilation. The original game was directed by Yoshinori Kitase, while everything else in the compilation has been directed by Tetsuya Nomura, relegating Kitase to far more hands-off producer roles. This, among all else, I would say is the chief cause for the drastic shift in tone between FF7 and Advent Children, a shift that ended up sticking to the rest of the compilation.