The Keynesian system of economics fails to model reality well because it's seriously flawed. The Austrian school of economics, which is similar to what was used in the United States pre-Keynes and whose economists did accurately predict the current economic crisis, is an entirely different matter. Look at Peter Schiff, Ron Paul, and a number of others -- they have been debunking Keynes for years. They've also been pointing out that the artificial "stimuation" of spending and the idea that your house is an investment rather than a liability or at best an item whose value is controlled by supply and demand and with the retirement of the baby boomers was bound to experience a slump in demand. With the addition of government interference in backing unrealistic loans for those who couldn't afford them, the writing was on the wall. We need to ditch the idea of a "centrally planned" economy and Keynesian economics generally if we want to have any kind of realistic understanding of how markets really work, and before we shoot ourselves in the foot yet again.