Les, the originator of this thread, mentions the "continuum of song". As an insight into the continuum have a look at Joyce's "The Dead". Two songs are thematically important in the story, one is "Arrayed for the bridal" (by Bellini?) and the other is "The Lass of Aughrim". The two songs, the operatic aria and the folk ballad, appear, as it were, side by side. There is no suggestion of hierarchy or even a hint that one is better than the other. Indeed there isn't even a suggestion that these are two different types of song.