99% of all FS releases are cropped from the widescreen version. You aren't getting more. In the vast majority of films shot in Super-35 you are never supposed to see the full area, only the widescreen area, its just a technical process and has little to do with composition.

Directors compose for the theater. Whatever the theatrical format is, thats what you are supposed to be seeing, and very few films have "open matte" fullscreen--half the time it reveals things like boom mikes and light stands that the matte bars are supposed to be obscuring anyway.