1969: One dollar = 1/35 of an ounce of gold.
2004: One dollar = less than 1/400 of an ounce of gold.
Stealth devaluation by Richard Nixon.
Could this be part of the reason?
no, neither the euro nor the yen, nor any other important currency is covered by gold.
Gold is a really good idea for monarchies or insane dictators, but not for a free market-economy.