Jim wrote -
"It seems to me that some people don't want them to have made them"

... and by his first them he is referring to the 'traditional singers' and by the second them he means the 'traditional songs'.

My main objection to this would be that we are are not dealing with what people want to believe. Roud's book makes it clear that he is following the modern academic approach to historical study when the researcher concentrates on evidence that can be quantified and not on any conjecture or personal preference. If anyone approached this subject saying, "I want to believe...." etc.etc. then they would find that their position would be difficult to maintain. The gap between "Belief" and "Knowledge" is a wide one based on different approaches to learning.