With all due respect to the Star Wars 77x0ae934r or whatever hell the number is, that is a totally different situation as there are other versions of the Star Wars 77 poster that are original that collectors can opt for that don't have the 3q43rqroqrqew numbers at the bottom. I sure as freaking hell wish there were two versions of the original Jaws poster. One for the idiots to buy that says 75232.0--3-4r3 and the regular one for sensible people like myself to pick up. But unfortunately, that is not part of the mystic of the Jaws 75 one sheet poster. Again, there is nothing post 70 that resembles the hype of the Jaws poster, nothing.
Reading through this thread, I'm not sure what is hard to understand about the Jaws poster pricing. The Jaws OS is probably the most recognizable movie image in the world. While Star Wars may have eclipsed Jaws at the box office, it does not have as broad of appeal. Also, as stated, there are far more examples of Star Wars.
As others have stated, many non-collectors desire this poster and want to be able to say that the one hanging in their home or office is an original from the 70s. Yes, normal people care about and desire this poster more than others from this period.
I would argue that the "Revenge" teaser for Jedi has a similar "hype" or "aura" as you put it, though on a smaller scale. The Revenge teaser is not rare, but commands huge numbers because of its perceived rarity and mystique.
Thankfully, I was a nerd in 1983 and purchased mine through the fan club for around 10 bucks. It is not in perfect condition because I was 10 and had no way of knowing that it would become valuable. But I would never replace it because of its personal history.