This is because he's never seen it.
He didn't write it. He didn't direct it. He's never seen it.
Looking back, it makes sense. There are parts of Return of the Jedi and the prequel trilogy that ignore, parody, and even contradict the events in Empire. Some of them are so egregious, you start to wonder if you know the film better than the film-maker.
Well, if you've seen the Empire Strikes Back once, congratulations: you know the film better than the film-maker.
Here is the first piece of evidence in my ongoing research:
1. The protagonist's character arc is resolved off-screen.
Throughout the trilogy, we watch Luke mature from an orphaned farm-boy into the most powerful being in the galaxy. The question is, will he use his powers for good or evil?
In a New Hope, he uses 'em for good. He frees a princess from prison, and delivers the coup de grâce in a major military battle. Great shot, kid! That was one in a million!
In the Empire Strikes Back, Luke flunks his lessons, ditches his training, fails to save his best friend, gets his ass kicked because he isn't finished training, and then the movie ends.
After the credits, there's a caption that reads, "By the way, Luke has two weaknesses: he's impatient, and he values his friends over the Rebellion. If he becomes evil in the next movie, it will be because of these weaknesses. Just FYI."
Will Luke learn patience in the face of chaos? Will he find a balance between friendship and idealism? Or will he submit to his vices? I can't wait to see how the writers handle this!
In Return of the Jedi, Luke drops villains like he's the goddamn Batman, and then a bunch of evil people ask him to become evil, and then he doesn't become evil, and then the movie ends.
The Empire Strikes Back asks, "If Luke is impatient and loyal to a fault, how can he defeat the forces of evil?"
"By being fucking awesome!" replies Return of the Jedi.
"Okay, but we just spent a whole movie watching Luke fail because he's impatient and loyal to a fault," persists the Empire Strikes Back. "How do you plan to show that he's become awesome?"
Return of the Jedi thinks hard. This is a tricky one. At last, its eyes light up. "I know! I won't show it at all! He'll become awesome before my movie begins!"
"But then you'd be a movie about a successful person being successful. That's not very interesting."
"Oh, I'm plenty interesting!" Return of the Jedi bristles. "In my third act, Vader threatens to ask Leia to become evil, which makes Luke go berserk! That loss of control hints that Luke might become evil!"
"Let me get this straight. Luke and Vader are fighting. Vader--who's spent three movies trying to kill Leia--threatens to ask her a question. This makes Luke and Vader fight again. And this, you propose, is a character arc?"
"Have you seen the Empire Strikes Back?"
"Ah, that makes sense, then."
Here's a way to fix the third act of Return of the Jedi: Luke is on the Death Star.
The shield generator is inside the Death Star, and if Luke destroys it, the Rebellion can defeat the Empire. Unfortunately, Emperor Palpatine is dangling Han and Leia over a shark tank...all the way on the other side of the Death Star.
This forces Luke to choose between 'saving his friends' and 'destroying the Empire.' Luke makes the hard, character-defining decision. But fear not, true believers: Vader redeems himself by carrying out the one that Luke doesn't choose.
Voila: we have a happy ending and a goddamn character arc. Cue the teddy bear luau. My, how helpful the source material is, when making a sequel!