Just stating a fact, not an argument. No, not all movies provided are on Netflix. Movies that are on HBO, Cinemax, Showtime, and Starz are not on Netflix. Netflix use to show Starz until the agreement was not renewed. They just show EPIX movies.
I had Epix on Dish Network, before I switched to DirecTV because of Sports. I really liked EPIX, they have exclusive rights to a number of titles, which you will not get in unedited non commercial form. The biggest being the Star Trek film franchise reboot.