I am not convinced. The U.S. economy is so large, and barriers to upper-class labor mobility across the Anglosphere so small, that I think the U.S. drags inequality trends in other English-speaking nations along after it.
Via Henry Farrell, Andrea Brandolini:
Why Is Economic Inequality Higher in English Speaking Industrialized Democracies?: What I really find conspicuous in the comparison of top income shares across rich nations is the similarity of the patterns observed in English-speaking countries as opposed to those found in continental European countries. It is striking that, after a prolonged period of moderate decline, the income share of the richest 1 percent suddenly began to rise in the mid-1980s in the United Kingdom, Canada, Ireland, Australia, and New Zealand as well as in the United States, while it exhibited no upward trend in France, Germany, the Netherlands, Spain, and Switzerland.
The difference between these two groups of countries confirms that market and technological forces cannot be the whole story, but the similarity of trajectories, including the time of the turning point, in the English-speaking countries defies an explanation based only on the national characteristics of the U.S. political process. Hacker and Pierson recognize the potential problem, but play it down by positing that the close interdependence of the markets for top executives can largely account for the common trends in English-speaking economies. Perhaps, but why should interdependence be so much stronger between London and New York than between London and Frankfurt in today’s highly integrated financial markets? Can common language be the only critical factor, or are there more fundamental reasons?