I see what you are saying, however the best classical performers are well-known for their own personal characteristics they impart to the music they perform.

Perhaps a violin in an orchestra is supposed to do what they're told, but they are told what to do by the conductor, who himself interprets a composition in the way he wants. And the best conductors are known for their brilliant interpretations, not their fidelity to the composer's intent.

Perhaps classical music has this reputation because there are a lot of really terribly uncreative musicians who would sound awful if given rein to improvise within looser constraints. I have met many musicians who are excellent ordertakers but not what I would call "musical" outside of that.