The US is economically successful if that means putting huge amounts of money into the hands of a few wealthy industrialists. However, it is the only indstrial society I have heard of, in which many people have to take on second and third jobs to be able to afford health insurance. It is also the only "modern" economy, in which nearly one per cent of its citizens is in prison and between a fifth and a third (according to which statistics you believe) have no proper health insurance. That would be intolerable in any Western European nation. Viewed in those terms, I would hesitate to call the US a "successful" economy.