Do you consider directors who don't write their own screenplay lesser filmmakers

Alfred Hitchcock was the most prominent director who never wrote the screenplay to their own movies. Neither did Howard Hawks. Martin Scorsese doesn't write most of his films. Close Encounters of the Third Kind and Poltergeist are the only screenplays that Steven Spielberg has written. David Fincher hasn't been the screenwriter for any of his films. All of them are obviously great filmmakers but it's a lot more difficult to write a great screenplay based on your own ideas and make it into a great movie than simply directing a film with the entire screenplay written by someone else. All of these directors are basically entirely reliant on the quality of someone else's screenplay to make good movies. If the screenplay sucks, there's not much they can do to make the movie better. How important do you think it is for directors to write screenplays for their own films?