It was; the astronaut corps, leery of being engineered out of their profession, lobbied hard for it. If I recall correctly, there's a brief discussion of the subject in
The Space Shuttle Decision [1], which I can recommend most enthusiastically to anyone interested in how this unique and remarkable spacecraft, and how the difference came to be so broad between what it was and what it was meant to be.
[1] https://history.nasa.gov/SP-4221/contents.htm