The Federal Reserve Bank, the central bank of the US, is not federal and also not a reserve bank. Since 1968, when redemption of pre-1963 Federal Reserve notes for gold or silver officially ended, and the value of the dollar by fiat (meaning the value is managed by the Federal Reserve Bank),
the dollar has devalued 90%. And also note that the purchasing power of gold has been quite boring consistent since it's use as money during for about 2700 years of existence (which have been used also by the entire world). If governments wouldn't spend unwisely, and central banks would regulate people might be like to hold gold less. Gold imposes a stricter and more prudent policy and also limits the amounts of money a central bank could lend.
As long as the bankers are not really regulated but take high risks until systematic shocks occur as a consequence. The regulation of banks should be done by it's central bank. However, all the commercial banks of the sovereign are required to be shareholder in order to get a license. So when all shareholders of the Central bank are taking huge risks and making money, it's very unlikely they will be regulated. In a sense Central Banks are national banking industry organizations who only serve interests of commercial banks. What has that trust of the value of the dollar and the Federal Reserve done for you lately??
Money is a store of value. What would you have your money on: as a store of value which has lost 90% of it's value and still loosing (despite being the most used currency) or gold which have been consistent in buying power since for about 2700 years.?
Even Central banks know it and they have, for good reasons, the largest stakes in gold. I know Bernanke says it's for traditional reasons that they have physical gold, but do you really believe banks that much are sentimental about traditions to have such quantities?
On the side, you bring it as if we all listen to the economists in their judgment about fixed supplies of stores of value, but that judgment is hardly unanimous. In fact there are more theoretical frameworks. But I am more of a pragmatist. You keep your dollars in your pocket and I keep my bars silver which I have bought many years a go. Let's put the theory aside and see how much purchasing power your stuff has against my stuff, I bet if yours looses 90% in 43 years we don't have to expect a sudden rise anywhere soon
;p
“Betting against gold is the same as betting on governments. He who bets on governments and government money bets against 6,000 years of recorded human history.” – Charles de Gaulle