I now know much pore about the history of pop music
I suggest that you read this comment on the book and compare it with the detailed analysis by Pseudonymous and decide which is the most sensible approach to the subject.
It would be fine to state your argument in the terms, I believe, that you advocate; that you are much more interested in the ways that folk songs originate than Steve Roud's interest in the way songs develop in the mouths of the people. An argument put forward in those terms would be met with respect and could lead to useful discussion and even to a greater understanding of the two approaches. A comment such as I quote at the beginning of this post is unhelpful, provocative and in no way carries the discussion forward whereas I would say that each of the ten points made by Pseudonymous carries careful reflection behind it and are all worthy of further reactions and observations.
I say this, Jim, in the hope that you will raise the standards of what you post here to that which I know that you are capable of rather than descending to trite barbs.