Your comparison to those superhero films is, in all fairness, not appropriate. They are "re-imaginings" and not intended to follow on from each other or act as prequels to any of the other films. We're talking about six episodes of one story. I know Lucas failed to match the trilogies up. He had to tweak the OT to fit the PT. So what? He's not perfect and I don't see anyone else trying to do what he's done.