You just KNEW I would mention the 1954 definition didn't you. It does NOT require a manner of performance. The material is handed down by the oral tradition (that bit needs re-phrasing, to allow for modern methods of transimssion) and is thereby modified. So pickling the style of delivery in aspic is not required.

If the material is folk song or music, then the nouveau-delivery is folk song or music and not "nouveau" at all.

The proposition is based on a failure of understanding.