I am just not seeing how a new story gets a pass, but an old one does not...especially when they were essentially the same story.A New Hope didn’t need anything because all of it was brand new. It was the very first story told as I already explained. As the story goes on though more explanations for certain events are needed. A new big bad after the Emperor and the Empire? Yeah, people might want to know where they came from.
I was fine with not knowing how the Empire formed in 1977 and I was fine with not knowing how the First Order formed in 2015 as a complete blow by blow back story was not needed to tell the portion of the story they were telling.