Perhaps Alex North’s musical score for Stanley Kubrick’s 2001: A Space Odyssey wasn’t right for the movie, but that doesn’t change the fact that North put everything he had into that score, working with the belief that it would be used. But Kubrick never intended to use it. He wanted the public domain music he selected himself for the temp track.
North’s daughter-in-law, Abby North, writes, “As all composers know, directors fall in love with temp tracks. It is often next to impossible for even the most talented and skilled composer to replace the temp tracks with new music cues that elicit the same feelings initially felt with the temp tracks. Unfortunately for Alex, Stanley Kubrick loved the grandeur of Richard Strauss’s Also sprach Zarathustra and the “poetry of motion” of Johan Strauss’s The Blue Danube in the context of 2001: A Space Odyssey.”
For a bit of context, see this piece on Kubrick’s use of European music in The Shining. “[A]lmost the entire score is made up of music by the best European composers of Kubrick’s time,” writes Hope Lies, Béla Bartók’s music in particular.