the us money supply is not based on gold reserves.
That is true, however I believe the comparison the NIA was makng is that in the real unmanipulated world an increase in money supply should be inflationary and as such all hard assetts should reflect that increase. There is a limited supply of things in the world that are deemed by humans to be desireable and as such with an increasing population and an increasing money supply those things should become more valuable.. I think NIA was pointing out that relationship without the human emotion that plays a huge role in the value of paper.