While a number of things are going down in value, printing presses of world economies are crankin'. Which is the justification from central banks for fighting deflation. "Don't worry, we are helping do our part" is the central bankers retort.
Bottom line is that while housing prices are dropping, commodities that have essentially inelastic supply are going up relative to the value of currencies, whose supply is growing rapidly.
Everytime the economy drops (like 2008), commodity prices take a hit. But they don't hit a lower low. If we have 10 dollars today, and the government prints another 10 dollars tomorrow, inelastic supply items would double in price. Might be some lag time, but that's just the way it is. Only ramping up mining and oild production would change the balance. Which takes time. All the while, they are printing more paper.