The real demand for commodities is still strong. The paper (speculative) demand has fallen off a cliff. So because you are buying copper wire at Home Depot, and not copper futures by the ton and taking delivery, your costs will only slowly drop. Price deflation will ultimately be outweighed by central bank inflation this time around (last time they waited until 1933)
Nice distinction between paper and physical. We even see this with gold paper at spot while physical gold is still getting $100 over spot. Well, last I checked.