@Todd_Spence And there is still score in the way you mean score, too. Go back and watch the scene where Karras is running around prepping for the exorcism while Merrin lays out the ground rules, for instance.
@Todd_Spence If you want to call the non-diagetic sounds we hear in the film, that are there to set the mood of the scene, “sound design” instead of “score,” be my guest.
@Todd_Spence There is plenty of score. It’s just not conventional or orchestral. Lots of animals noises and other weird sounds. You are hearing it but not clocking it as “score.”