Capitalists feared workers. Catholics and Protestants alike feared the forces of militant atheism. It is no accident that a large proportion of the highest British electoral turn-outs were recorded in Northern Ireland, the most deeply divided part of the country. In 1951, turn-out in Fermanagh and South Tyrone was 93.4 per cent. Today, except in Northern Ireland and places like the Balkans, those old tribal feelings and loyalties have largely disappeared.
Most Western countries are far more at ease with themselves now.
The voters may still be discontented with their politicians but they are far more contented with one another. The second explanation is related. Not only are the voters today less tribal, the political parties are much closer ideologically than they used to be. The Communist parties of France and Italy have all but disappeared. Left-wing parties everywhere have largely abandoned socialism.