Toby, I would suggest a really interesting article by JD Vance that speaks to this point quite directly: “How the White Working Class Lost Its Patriotism.”
The very compelling argument here is that the media portrays the voters who are supporting Brexit or Trumpism as “angry,” partly because that is a word and a concept that the media is comfortable with, when in fact that are often simply alienated or afraid. They see progress, but they don’t partake in it, nor do they fully understand or feel its implications.
According to Vance, what is often interpreted as anger is in fact manifested in a deep sense of alienation from the political class, and from the nation itself among working class people. So for example, we call white working class Americans who suspect Obama of being a foreigner as racists. But in part, this also reflects the fact that Obama has benefited in every way from the changes America has undergone in the last few decades, and as a result, he is a sort of person that these people do not recognize or sympathize with at all. If he were white, they might think that underneath his polish and charm and CV, he was just like them. But because he isn’t, there is no veneer of familiarity- he is as much a foreigner to them as is Angela Merkel.
As the west has grown richer, and financialization and technology have transformed the lives of those living in centers of innovation (the East and West of the United States, London, Berlin, Prague etc), the gospel of opportunity that western democracies preach has become less attainable for those populations with deep ethnic ties to their communities. And white Americans and Britons never before, in all of history, faced sidelining of their way of life, or the erosion of their self-image as the heart and soul of their respective countries. If they didn’t always share in all the wealth, they at least felt that they could share in the wealth with a bit of hard work. But now they are not needed anymore, and that is an alienating truth.
In sum, progress over the last 30 years or so has favored those who have not made patriotism and ethnicity a central part of their identities, and to those who have, anger and resentment appear on the surface to be the only understandable reaction.