Why no new Christmas carols?

Historically it’s been nearly impossible for a new Christmas song to break the impenetrable monopoly of “Away in a Manger” (1885); “The First Noel” (1823); “Oh, Come, All Ye Faithful” (1743); “Silent Night” (1818); “Deck the Halls” (1862); “Jingle Bells” (1857); “We Three Kings” (1857); “God Rest Ye Merry Gentlemen” (17th century); “Hark! The Herald…