The collapse of authority and the establishment, yes. But Duty wasn't imposed by an authority. There's a quote that I can't find at the moment with the effect of "no-one can tell you your duty, it's something you must discover for yourself".
totally agree that it's metastable. Which is why I found it fascinating with the Shame connection - shame appears to be metastable too
It seems to me that duty has more to do with collectivist feeling in general than nationalist feeling specifically (which is just one subtype of collectivist feeling). You have duty if you belong to and care about something larger than yourself. I think what's weakened people's sense of duty is the wave after wave of increasing individualism that probably accelerated some time after WWII, and has been going on for as long as I've been alive. A big part of duty is sacrificing your individual interests for another, which has always been hard but is even harder if social attitudes don't give it much support.
I can imagine that having a tangible cultural impact, particularly around our sense of collective ownership and duty.
For example, you shouldn't litter, and if you see someone else doing it, you have to overcome your shyness and point out to the kids their duty. And if you get busted littering, you should feel bad.
The thing that happens when authority breaks down is everything else is questioned too, whether or not that authority had anything to do with creating the pre-existing norms.
http://bostonreview.net/books-ideas/samuel-moyn-rights-dutie...
I'm curious to know if this is really true, or if that aspect of history was written and romanticised by the people with the power to do so, who benefited from that.
It strikes me that there was also a spirit of rebelliousness in the mid-20th century: unionisation and industrial action was also at its peak.
You go to the park, you see a kid littering, you tell them to pick up their trash. They tell you to mind your own business, and make YOU feel bad about talking to a child who isn't your own.
The problem with the duty system you mentioned is it needs a lot of buy-in. It's like it's metastable, it works when there's buy-in, but generally it doesn't work. As soon as someone is willing to question it, it falls down. "Who are you to point your finger" is surprisingly effective at reflecting shame.
In the mid-20th century we were still at the height of nationalism. People thought to be English meant you had to do certain things, believe certain authorities. During that century, people started to notice the cracks and it all went.