It's true, the nordic countries do well on Social Mobility [1] (measure of intergenerational economic mobility). However, I think we can all agree that they're fairly homogenous ethnically & culturally (e.g. as measured by Fearon's measure [2]), and that these factors play a huge role in social mobility in places like the United States.

In fact, if you jointly score social mobility & ethnic diversity, the United States looks to come out very close to the top (if not the top). It's probably not a "one size fits all" solution, though social safety nets are obviously a critical part of the equation.

[1] https://en.wikipedia.org/wiki/Global_Social_Mobility_Index

[2] https://en.wikipedia.org/wiki/List_of_countries_ranked_by_et...