AFAIK protestant work ethics are rooted in Calvinism, which heavily influenced many sects in the U.S., but not or to a lesser degree the northern european countries.
Even more interesting because I consider Netherlands the closest you get in Continental Europe to a Scandinavian country (socially/economically speaking).
May be protestantism is the origin of this kind of work ethics, probably exacerbated by american history (colonising a new world, carving a new place for themselves in a barely-known land...).
https://en.wikipedia.org/wiki/The_Protestant_Ethic_and_the_S...