...Gerrold pitched "The Protracted Man" but CBS rejected it because it was "unfilmable" at the time.
The Star Trek
production rejected it, not the studio, which nevertheless would not
have been CBS in 1967, but probably Desilu.
As I recall from Gerrold's book, there were other issues with the pitch beyond the expensive "West Side Story" effects, including that it focused too much on the guest characters and not the crew.