Has anyone written a social history of song in communities where singing was still actively practiced during the 20th century. That is, after the period after that covered by Roud?

What are the differences, socially, between singing on the cart coming back from market in 1755 and in the back of charabanc coming back from a works outing to Southport in 1955?

Why do people 'draw the line' where they do? There seem to be many times where one can pick point to a significant change - Jim's account of Travellers getting TV in the 1960s, recorded music in the 1920's (+/-), change in farming following the WW1, Music Hall in the towns, the gradual move of populations from country to town etc.

Where will people 'draw a line' through communal singing in 100 years time?