The top 50% of Americans are better off than the top 50% of people in Sweden. That's 160 million people doing better than Sweden, I call that an extraordinary success.But it has little to do with the differences in the two economic systems. The USA is rich because Europeans discovered a very large geographically isolated land mass that was only thinly populated by pre-literate people with technology that was primitive even by ancient standards. How would you not expect such abundance to produce an extremely wealthy society?
Sure, settling a continent and building infrastructure up from nothing is hard work, but Europeans had a couple of millenia worth of practical experience and how-to manuals on the best way to go about this, and cheerfully reinstituted slavery, which had worked out so well for the Roman empire. Without denigrating all the genuine hard work and innovation deployed by many generations of settlers (and not only from Europe), their labor was far from the only economic input. The US has vast tracts of agriculturally productive land, huge mineral wealth, and extremely favorable strategic geography. If you could go back a few thousand years, wave a historical magic wand and give ocean-capable shipping and navigation to the Romans or Han Chinese, they too would have established a mighty economic and military empire on the North American land mass.
I'm broadly pro-capitalist, but I can't take you seriously when you ignore the massive economic advantage of being practically handed an entire continent to play with. You would have to be staggeringly incompetent not to become a world power.
The bottom 1/3 are better off in Sweden than in America however, not much debate on that.
Not only does Sweden not have the same sort of permanent underclass that the US seems intent on cultivating, they probably don't spend as much of their wealth on security services designed to protect the property of the well-off from the poor, whereas something like 1/5 of America's labor force is devoted to guard labor: http://tuvalu.santafe.edu/~bowles/GarrisonAmerica2007.pdf
While the US is certainly wealthier in fiscal terms, this country does have some massive quality-of-life problems, and there's an almost pathological antipathy to measuring the cost of economic externalities - another symptom, I suggest, of having so much land available.