World building is an elaborate affair, and can get in the way of the storytelling if you keep having to stop to explain how something works. If you have a pre-made world to put your story in, why reinvent the wheel?
On the other hand, burning the whole thing down and scratchbuilding a new science fantasy universe might be the only way to deal with Star Wars' toxic fans.
I think the story telling is the most important part and the world building should be only when the story requires it. Even Star Wars did this.