My pet theory on this is that the divorce during ROTJ broke George, and his former love for Marcia curdled into a resentment that he ever loved her. (Being a child of divorced parents, I speak from some experience here.) Star Wars – which as we know she was originally such a creative influence on – become a proxy for his desire to never have gotten involved with her; basically, the creative team at LucasFilm and us the audience all living inside his bad divorce.
I have thought of something similar. It's a love/hate push-n-pull, the way I've seen it. I've seen this with Hideaki Anno with Evangelion. You said all you wanted to say originally years ago in what became your masterwork, and there was a lot of good and bad that went into it; but people want more, and not just more, but more of the same. So as time progresses, and you're working on the same thing you already detached yourself from, you revisit and change ideas just to keep yourself from getting bored. George is business-savy enough to let others play with his "universe" to keep the name alive and keep his company afloat (when he had it), but as we have seen and continue to see, it just becomes a stagnant beast that eats and regurgitates its own feces.