I'm afraid that some of this continues to go round the same circles.

(from Jim) "That the broadside writers were poor poets is beyond question"

Many of them, yes, but not all of them. Some known poets turned their hands to broadsides on occasion. And the same poet might produce a gem one day, when inspired and having some time to perfect it, and a pot-boiler the next.

(from Jim) "One of the features of writers writing on subjects outside their own experience is to produce pastiche - plenty of examples in the broadsides and from the songs of the stage and pleasure gardens - Dibden made his name producing such dross."

Many songs that might be considered pastiche or dross nevertheless caught on and eventually got collected.

(from Jim) "As far as I am concerned, if working people were capable of making their songs (some of you have paid lip-service for them being able to) then they probably did."

It is not lip-service. Everyone here agrees that working people could and did make songs.

It is however undeniable that, whoever first made a song, if it was printed on a broadside it stood a much better chance of being widely disseminated and therefore a much better chance of eventually being collected than a song that never saw print. Therefore the songs that were collected were bound to be mostly songs that had been printed. That tells us nothing about who created them; and for most of them there probably never will be definite evidence.

There is internal evidence, in the style of wording, in the use of recycled text and in the subject matter, but that is not conclusive. A good novelist gets inside the characters, making them and the events of the story believable, whether or not based on the novelist's personal experiences. Why should it be different for a good broadside writer? Then again, many of the stories are obviously fictional.

(Now re-typing a chunk that disappeared) To throw in one further thought: there are plenty of songs about the press gang, plenty of "last goodnights", plenty about lovers kept apart by parents or getting together despite parents, umpteen broken tokens. There are songs (widely disseminated if not so numerous) about poachers getting caught or not getting caught. But how many about the Enclosures? There are songs about happy marriages and more about unhappy marriages, but how many about the joys and frustrations of parenthood?

There are songs about hardships at sea but how many about back-breaking toil on the land or in the mills and factories? There are songs about strikes (mostly from known 19th century writers) and mining disasters, but how many about routine work? (There are some.)

People have been building dry stone walls for thousands of years, but as far as I know the only extant songs on that subject are modern ones.