1990osu said:
Let's see what 1970s George Lucas has to say about grain....
Lucas in American Cinematographer, October 1971:
"I was well aware that there would be those in the audience who would be shocked by the graininess at first, but I was sure that after the first minute or two they would get used to the grain and simply accept it as part of the stylistic concept, the documentary approach."
That really don't apply to Star Wars though, as Star Wars is a Panavision film and THX 1138 is a Techniscope film. It's a big difference in grain structure between the formats. But that doesn't mean Star Wars looked like the blu-ray, far from it.