I'd say it's about quality....and respect to three films upon which great importance is placed.....not only as an influence to a generation, but as a benchmark in SFX evolution and a milestone in American cinema. There is no difference between these films and Citizen Kane, Casablanca, Lawrence Of Arabia or The Godfather. They are all important pieces of art in the history of American film and they deserve to be preserved so future generations can see how cinematic art progressed in the 20th century.....

Oh....and naturally cuz Lucas just plain HATES that we want them and not the SEs.....