5) What makes 19th century rural England so different from Rural Scotland or Ireland, where folk song making is a proven fact?

Others have already addressed the Bothy Ballads issue. I was the one who originally suggested the Bothy Ballads. Although I can't claim to have conducted individual studies on Bothy Ballads I am very familiar with them. Perhaps it might be more relevant to look at the Greig-Duncan collection, a very large body of material but much more representative of North East Scotland. Much of the material in G-D is a very mixed bag. There aren't that many of the big ballads in relation to the whole corpus, there are lots of local songs not found elsewhere, there are also lots of broadside ballads in there, as you would expect crossing over with what Sharp and co were collecting, and a whole load of Burns type stuff again which you would expect.

As for comparing what was going on in rural England in the early 19th century with conditions in rural Ireland in the second half of the 20th century, well I'll leave that to the historians to answer.