Don't give up your day job. Economics is not your strong point.

The US dollar hasn't been the global currency of trade since Nixon removed us from the Bretton-Woods treaty. The investors of the world desire dollars because they understand that America can never run out of them and its economy will remain strong through most downturns. The Fed provides a very convenient clearing bank for international trade at no cost and Treasury even offers interest bearing parking for any excess dollars accumulated. Since Treasury only accepts US dollars, it can never involuntarily "go broke" or fail to pay any obligation.

Now, if we can just make our elected politicians understand this we will fare much better than we have for the last half century of deficit hawk leadership. Their reluctance to fund the American economy (which only they can do in net terms with deficit spending) has brought the US to the point where investors are looking around at alternative currencies as a safe store of value.