I would not call 2001 – A Space Odyssey a groundbreaking film score though (not that I’m saying anyone here did), it’s obviously not a film score at all, it was a movie that just used classical pieces of music. Obviously, to great effect and iconic use, a milestone “soundtrack”, no doubt, but nevertheless not an original score.
This depends on whether you are considering what constitutes a “score” from the perspective of process vs. function/effect. The music for 2001 does not meet the criteria of a score in terms of process, but it does in terms of function and effect. In the context of a film, I’m more interested in the latter.