Just had a look at the 'Answer' on a Pitts broadside. Rather interesting. Answers were not usually printed unless the original had been a success. It was certainly far from a success according to Roud. However it has been a resounding success since 'Marrowbones'. I even heard an Irish country version of it in Fleetwood Market.
It may well be that the song was considered to be an Art production and not noted by the early (Pre-Sharp) collectors, in the same way as Sharp ignored early Music Hall material. All speculation of course.