That is true in the long run, or probably even in the medium run, but in the short run, there has been a lot of fear-based speculative buying in the commodities market. Recall what happened to oil a couple of years ago. Commodity markets are naturally highly volatile in the short term, and there's no reason to expect that to change. The problem for a market for any good where the price is rising very rapidly in the short term is that it requires a constant stream of new investors to enter the market at higher and higher prices; eventually you run out of buyers who can afford to play.
Originally Posted by Marco B