"One of the many things that has occurred in the last century or so that has stemmed the flow of oral tradition is the acceleration of fashion change, mainly due to modern technology. Something comes into fashion and rapidly disappears as something else comes along to replace it. Consequently only the very memorable items take a hold whereas prior to this they had much longer to take a hold."

Yes, but it doesn't disappear anymore. It just gets archived on youtube. My kids can listen to the same recorded tunes that I did when I was small, and wax cylinders of 19th century music hall music is there, too. Currently, string band music is rather popular (Cornbread and Butter Beans)

Original archived recorded material is a click away. The Bristol Sessions

Somewhere out there, perhaps someone is learning Lord Bateman from Elizabeth Laprelle, who currently makes a living singing it (does that make it a pop song?)