This is only true if you ignore the important material and historical factors that go into the success of a country. Like for example, the immense wealth of natural resources and variation in climates that the US has. Or how about escaping much of the devastation that Europe faced in WW2 and benefiting immensely from helping them rebuild. Or having (for the most part) incredibly safe and stable relationships with neighbors to the north and south. Free markets have certainly contributed to success, but to say it's the only unique thing about America is just wrong.