First, increased complexity and dynamism makes more room for other inequalities than ‘just’ financial inequality.
Second, the higher average income/capita or average net worth/capita is nominally in US $, the more people/voters are concerned with other socio-cultural issues than the economy.
Third, as very few progressives/leftist’s have pointed/figured out, the more immigration the more cultural conflict on other issues than the unequal economy.
Fourth, this will be more important in the future. Rights and entitlements must be coupled to citizenship, or else the egalitarian prospect will only ever rise again after the illiberal oligarchs, plutocrats and corporate semi Fascists have procured what’s left of the Neo-liberal projects in America, UK, and much of the dysfunctional Eurozone.