I would agree broader cultural forces were part of the picture.
Here in Cape Breton there was a famous documentary “The Vanishing Cape Breton Fiddler.” And indeed, they were vanishing in the 60s and 70s; I rarely heard trad music at that time in Cape Breton. Us youngsters were far more interested in rock and roll. Trad still existed only in kitchen parties in the rural hinterlands.
It was ironically this documentary that stimulated the remaining fiddlers to mobilize, form a promotional association, try to revitalize the traditional playing style, music, etc.
This parallels the trajectory of the UPs, even without the challenge of getting hold of a functional set that is the bane of piping. Fiddlers can actually play violins and lots of those could also be come by at much more reasonable ( I’m only alluding to affordability here, not the time and skill to produce UPs) cost.
I did hear and have some interest in the GHB as a youngster, but the military tradition didn’t interest a rebel such as myself. And in any case, my mom was not keen on a GHBer in a large family with a small house. Sensible enough.
Later I met the MacNeils from the group The Bara MacNeils, who while hailing from Cape Breton, were heavily influenced by Irish trad, and had a greater variety of instruments and styles that the usual Scottish influence fiddle with piano accompaniment typical here. The Barras were part of the trad music revival here in Eastern Canada.
It took a live Chieftan’s concert though for me to get a UP obsession (thanks Paddy!).
A younger sibling of the family group The Barra MacNeils went on the play the UPs and I had many a fine tune with him over the years until he married a South African lady and moved to the country. My daughter now takes violin (fiddle) from one of the older Barra MacNeils, and although she is more interested in classical repertoire she plays more trad because you just can’t escape it.
The film maker responsible for the "Vanishing Cape Breton Fiddler’ is talking about doing an updated documentary.
Anyway, a strong parallel with trad music tradition based on the fiddle here on the other side of the pond does suggest the importance of broader social/cultural forces at work.
Mike