Why music rights?

As noted in the previous post, all pre-1923 works are in the American public domain.  That includes such instantly familiar tunes as "Yankee Doodle Dandy," "Row, Row, Row Your Boat," and "Jingle Bells."  Yet every actual recording, regardless of release date, is protected by copyright.

To use a pre-existing song in a movie or on a TV show, the producer has to receive permission from the artist(s).  A 2009 book on low-budget filmmaking claims it may cost hundreds of thousands of dollars to use a single song by a band as famous as The Beatles.  But less renowned artists—say, ones you would not usually hear on the radio—are comparably cheaper.

Compilations by "various artists" claim to have the original recordings of the songs they present, but in truth, some are either by cover bands or consist of re-recordings by the original performers several years later.  Such anthologies usually (frankly) stink, but the compilation process would probably be more difficult had they used the original versions.  In fact, the 1969 hit "I'm Gonna Make You Love Me" was a duet between The Supremes and The Temptations, perhaps to make recording less complicated, as they were both Motown acts.

As with copyright in general, music rights are neither as democratic nor dictatorial as they could be, but they serve an overall good purpose.