You think the distribution of living standards across a population could be a matter of social norms? How?
Taxation and social programs:
* https://en.wikipedia.org/wiki/Redistribution_of_income_and_w...
People choose to vote for / elect people who are willing to implement various policies to achieve it. What is acceptable to the population is (partly?) determined by the norms of that population and society, and the acceptance of various ideas will determine what politicians will campaign for.
Social norms come first, and they determine which economic policies you are willing to even consider (and then implement or not).
Japan's economic system has been under Japanese control and self-determined (for both good and ill) for decades:
* https://www.goodreads.com/book/show/16144575-how-asia-works
But is that because of their economic policy or because of social norms?
> It might not look good according to metrics that optimize ploughing society's wealth into the hands of a few billionaires […]
Sweden also has a pretty good standard of living, less inequality than the US, decent economic growth (better than JP, lower than US), and has more billionaires on a per capita basis than the US:
* https://en.wikipedia.org/wiki/List_of_countries_by_number_of...