I think there will always be more to it then just a simple prompt, but having the vision to make a song that sounds pleasing, and unique enough is certainly creative to me.
Of course, there's also a huge demand for generic, inoffensive music (think theme/intro songs, waiting room and elevator music). If we could make that more enjoyable to listen to, would anyone care if that's not creative thinking?
You could make (and many do) the same arguments over covers of songs, even when the covers end up eclipsing the original. Where was the creative thinking in that?