Also, the US government doesn't really have anything to do with the USD; the USD is managed solely by the Federal Reserve, and the Federal Reserve is not a branch of the US government (it's a privately held bank; look it up).
"it's not nothing"
It's worse than nothing. The Federal Reserve can and does change the value of the dollar at will (it's called inflation). That's why you can buy a loaf of bread with your 5 bucks now, but in 10 years your 5 bucks probably won't even buy a candy bar.
Contrast that with gold. In 1913 (the year the Federal Reserve was created), you could buy a house with 100 ounces of gold. 100 1913 dollars is worth roughly 2 2013 dollars, but 100 1913 ounces of gold is worth exactly 100 2013 ounces of gold, and you can still buy a house with it (100 ounces of gold is $156,740 USD; no, this won't buy you a house in New York, but it will in most other parts of the country). That's what it means for a currency to be backed by something of value. Value doesn't change.
Just to pick some other dates:
100 ounces of gold in 2000 was worth ~$28k which wouldn't buy much house anywhere.
Also, comparing gold @ ~$20/oz in 1913 to a dollar stuffed under a mattress in the same year is a bit of a false comparison. The Compounding the same $20 in 10year Tbonds (a decent 'risk free rate' starting in 1928 (the first year I could find data) would yield ~$679 in 2000 (outperforming gold by over 2x) and ~$1385 in 2012 (underperforming slightly, but with almost no volatility).
You can't compare gold just sitting there with USD gaining interest in an investment for 90 years. Well you can, but then you'd be making a ridiculous comparison.
Tbonds are pretty much the definition of the "risk free rate of return" for USD. Is there an alternate (non-zero) "risk free rate" for gold that you would like use instead to make comparisons?
Because you're comparing the value of one thing over time against the rate at which you would gain value in a different investment over time. I can see an argument for why you might say tbonds have been a better investment than gold, per se, but that's not what I'm talking about. I'm talking about the necessary volatility of fiat money because it's not backed by anything of real, unchanging value. I'm talking about the purchasing power of the same amount of gold and USD over time.
"what are you using to measure the "volatility" you claim fiat money has so much of"
Inflation.
And 'unchanging' wasn't the best choice of words, but my point is that gold is not subject to the whims of monetary policy makers because you can't create more gold. Gold's value only changes when more gold is discovered.
