[Nick Zwar]

Yes, I agree. Film music is film music, it is not an opera, not a tone poem, not a ballet, etc. but it can incorporate and even “be” all of those things. There are certain things that set film music apart from non-film music, just as there are certain things that set ballet music apart from non-ballet music. But like in film music, the difference between ballet-music and non-ballet music is contextual, not inherently musical. Which is why you can perform ballets to non-ballet music, and perform ballets in concerts without any stage presentation. (I’ve seen a number of complete ballets performed live in concert, including the Firebird and The Wooden Prince.)
If you take a look at the full ballet of Stravinsky’s THE FIREBIRD, that’s very “filmic”. The main difference is that the “tracks” segue into each other (as THE FIREBIRD is about 40-50 minutes long with clearly different “scenes” but few “breaks” in between), whereas in film music, you have “stop and go”.
Still, if you pick a cue out of THE FIREBIRD and put them next to a cue of some film scores, uninitiated people (those who wouldn’t know either composition presented) likely may not be able to assert which is film score and which isn’t.
Stravinsky is a very “filmic” composer anyway.