I heartily endorse Will Fly's comment about audience enjoyment. What makes folk music interesting for me is the way that the same song can be taken and almost endlessly reinterpreted by different performers with innovative accompaniment on different instruments. Of course, we need to hear the words, but how they are put across is what adds interest. Let's face it, most of us know many of the traditional songs word for word, so to hear an endless stream of 'groaning old folkies' singing the same songs in the same way is mind-numbingly boring. I would cite artists like Martin Simpson, Martin Carthy and Lucy Ward as good examples of how traditional songs can be reinterpreted to make them new, but there are plenty of others who are doing this.

Clever variations on a theme is what keeps the songs current and interesting. After all, Vaughn Williams' Variations on Dives and Lazarus would be pretty boring if it was just the basic tune repeated over and over.