For years I wrote in my basement. More recently I graduated to one floor above, an office with all my books and music and - ta da! - a window.
I don't think you can replaces great themes. But I think people do want to hear fresh arrangements of them. They don't want to hear them played the same way all the time.
Also, since art is a vehicle for the transmission of ideas through form, the reproduction of the form only reinforces the concept. It is the idea that is being reproduced. Anyone who understands the work of art owns it. We all own the Mona Lisa.