I think it's culturally and socially driven. As an outsider looking in I have discussed American capitalism with others and its more ruthless nature compared to the more moderate varieties of Europe. The US GDP (ppp) per capita is very high for the size of it's population (and not being a tax haven or major oil exporter). Even compared to a wealthy powerhouse like Germany the US has a gdp per capita $10k higher. I don't believe that is due to the Us being a more efficient economy. It's because US employees and citizens aren't afforded the same services, rights, and level of care that people in countries like Germany do get that alleviates the stresses of daily life.