"Jim, the evidence you keep bleating about lies in the songs themselves,"
Not entirely true Steve, unless you totally disregard what the few singers (and ballad sellers and buyers) that were asked had to say, which apparently you do, as you have pointedly not taken them into consideration in your 'analysis'. As far as I am concerned, these are the sources of our material and could be a way to a greater understanding of it if we pull together what little was got from them and examine it closely. To separate the songs from those who sang them and possibly made them , and the communities that kept them alive, is an act of almost criminal negligence in my book.
The song texts give some clue to their origins; use of vernacular, familiarty with subject matter, etc., which you have persisted in avoiding discussing the implications of.
All of this is sparse enough, but coupled with earlier scholarship - which apparently you have written off as rose-tinted romanticism, it beats hands down (IMO) desk-bound paper pushing and head-counting, and I suspect you are aware of this, from your reluctance to discuss it.
There is an undeniable link between our songs and ballads and print, but it is by no means as simplistic as you make out. David C Fowler did some fascinating work on the subject, research that places the origins of many ballads much earlier than the broadside presses. He also places the ballads on a far higher plane that your putting them on par with Lennon's and McCartney's output, and the people who kept them alive through the ages as being no different than attendees of a Boyzone concert.
My objection to what you have to say is not that I disagree with it; rather that its is set in such arrogant finality that it rules out further discussion.
         
The truth is, we don't know the answer to who made the ballads and songs, and probably never will, and to pretend otherwise is disingenuous and damaging to further understanding.

I did find your patronising tone somewhat amusing at first; I am now finding it downright insulting. You appear to counter the work of those who disagree with you by denigrating them as researchers rather than being prepared to discuss their ideas head-on - I'm a hopless romantic, Leslie Shepherd was an ignoramus when it comes to folk-song, Peter Buchan was a liar and a cheat - not good scholarship in my book, and certainly not the way to an understanding of a complex subject.
Absence of definite knowledge is best handled with a degree of humility, which you apparently lack.
Jim Carroll