There's no reason why the US can't be higher. Reuters:
The index is based on a definition of prosperity that combines economic growth with the level of personal freedoms and democracy in a country as well as measures of happiness and quality of life.
With the exception of Switzerland, which came in at number 2, Nordic countries dominated the top 5 slots, with Sweden in third place followed by Denmark and Norway.
The top 10 were all also Western nations, with Australia (6th place) and Canada (7th place) both beating the United States, ranked 9th. Britain came in at number 12.
