I don't dispute the definition - it is what it is. But, if that is our standard, much of what we have been hearing and performing over the past 50-60 years or more will have been disqualified as "composed." Though I have affection for many of them, I seriously doubt that there is, in reality, a very broad audience for songs that spring only from the oral tradition. They are for scholars to pursue; a rather arcane pursuit for a passionate few. To be frank, for most modern audiences, even in the coffee house venues, you can only do songs like Barbara Allen or The Golden Vanity so many times before eyes begin to roll back in the audience's heads.