"How many times do we have to state that we all believe implicitly that country people are well capable of making songs"
And how often do I have to point out that 94 to 100% indicated that that "belief" is little more than lip service - confirmed by your passing of such writings as that of retired farmers writing about their own experiences
If you accept that country people were capable of writing our folk songs than you have to concede that they are the most likely candidates for having done so, all else being taken into consideration
"There is nothing special about the art of the broadside writer. "
I agree absolutely - their work is almost uniformly poor and shows all the evidence of being hastily carried out
I've asked that you point out a collection from those I mentioned that include singable songs
Nothing so far
"So Hawkesbury river and Australia are not reference points then?"
Of course they are, but not necessarily to the songs
You have described Bob Thomson's theory as unconvincing, yet he gives the song an Australian context by setting it in an area which included a returned convict settlement, where you would place it's origins in the City (Glasgow and Manchester, wasn't it?)   
Jim Carroll