That's interesting vibrato, though I don't agree completely. That kind of film is still being made, but is not very common. Examples are the first Batman, which had a complex, contrapuntal, excellently orchestrated Herrmann-style score (though not orchestrated by Elfman), and Lord of the Rings which is a perfect example of a Max Steiner-Korngold style score that Shore did the orchestration for himself.
However, it is now possible to do music with none of that excellence or complexity. A "composer" (usng the term very loosely) can noodle with his synthesizer and give the results to an orchestrator on a sufficiently high budgeted film. This is then converted into a score like Last of the Mohicans, which is not a film score at all. It is one short little ditty that a chimp could have composed, played over and over again with a few extra chords. These things are not film scores, and the people who do them are not composers. They are sound effects technicians, because that "music" is not music at all. It is simply a sound that is being used to affect the scene. So it is partly because of these changes you mention that more than one kind of "score" is possible today.
Anyway though the way the orchestration is done is highly variable based upon the people and the film involved, so you are not confused. There is no one way it is done. It is true that Herrmann did his own orchestrations entirely, and I remember Dave Connor stated previously here how he saw the detailed sketches Goldsmith did that were so involved that the orchestrator had very little to do.