Some might be legitimately lost outside of digital versions preserved illegally. I'd assume only a number of copies are owned by people who have purchased the m

Some might be legitimately lost outside of digital versions preserved illegally. I'd assume only a number of copies are owned by people who have purchased the music legally (who may not know where the music is located or know how to go about sharing it) and that the record label has lost it in their archives at some point (or may no longer be around at all).