This has been going on for several thousand years now. It's call economics, at one time it was salt, rocks, pelts, as the medium of exchange.
Major rule (econ 101- large supply small demand prices fall until the supply curve meets the demand curve- we have huge supply, and small demand (demand is not what people want but what they can get)
Going down more it looks like - cap and trade - then we are talking really down, Last I saw many are calling for Florida prices to drop 21% more in next 12 months. So it may get even more fun.