>>211356462It's because contrary to his later claims, Lucas did not have an extensive backstory for Vader or the Force. The original Star Wars was just a love letter/plagiarism (depending on who you ask) of shlock 60s scifi serials, kurosawa, westerns and WWII movies. Vader was just some mid boss mook sent by the big bad guy to job to the hero. He didn't have a tragi-comic history nor was the Force and Jedi truly fleshed out. That's why you see Imperial officers treating Vader with disrespect because he is not part of the formal chain of command and the Jedi were supposed to have been gone for hundreds of years instead of only 20.