An interesting take on history, by what terms is the USA the most successful? You also differentiate the US system as a separate economic system, the defining characteristic you presented were not particularly unique to the USA.

It could be ventured that the Roman Empire, the Mali Empire or any number of Chinese dynasties were far superior by multiple criteria.

My personal flavor of preferred economic system is a mixture of socialism providing essential services and strong capitalism in sectors requiring the dynamism that competition provides.