Lucas's genius was cobbling together all those elements into a new and genuinely exciting format. That's what made Star Wars work. It might not be original but its fundamentally a very good action-packed coming-of-age story and it hit the cinemas at a time when there was a dearth of such stuff. In other words, George Lucas got lucky.
Better stealing 633’s dialogue than their special effects. ;)
Really? I'm going to have to look this up. I always thought the final battle scene of Star Wars was a mashup of Battle of Britain (which also has surprisingly similar dialogue) and The Dam Busters.