There's always been a lot of talk to the effect that Swedish egalitarianism is perhaps a product of longstanding cultural development.

If this study is correct, that's not the case.

See:
https://academic.oup.com/past/advanc...gtz010/5498958

"Abstract

During the twentieth century, Sweden became known as a country with an unusually egalitarian distribution of income and wealth, an encompassing welfare state, and an exceptionally strong social democracy. It is commonplace among historians and social scientists to consider these equal outcomes of the twentieth century as the logical end result of a much longer historical trajectory of egalitarianism, from early modern free peasant farmers or from a peculiar Swedish political culture that was egalitarian and consensus-oriented. This article questions the Swedish interpretation of Sonderweg. In 1900, Sweden had some of the most unequal voting laws in western Europe, and more severe economic inequality than the United States. This throws the purported continuity from early modern equality to social democratic equality into question. The roots of twentieth-century Swedish egalitarianism lie in exceptionally well-organized popular movements after 1870, with a strong egalitarian counter-hegemonic culture and unusually broad popular participation in politics."