The OP has a valid point. I brought it up two years ago here, and was ridiculed as a tin hat foil wearer. And I'm not even predicting a depression, simply mild deflation. Now look where we are.
Housing is deflating to many trillions. Derivatives (CDO's and such) are too, Goldman estimates to 1T (the estimate progressively gets higher over time). Auto's are in depression, airlines have been so for a long time. The only thing inflating is energy and commodities, and that's probably due to speculation (since commodities are the new undiscovered asset class) Wall Mart et. al. have dropped prices hugely to retain market share.
Mild deflation? You bet, and notice what's happened to long term Treasuries? They've been doing very well. All it will take to cinch it is consumers continuing to retrench. Given the state of their retirement funds, and that they've been spending more than income by 1-2% each year for 25 years (fueled by credit growth, internet bubble, and housing in that order), I don't think it's unreasonable to expect this to continue.
I have private paid research which investigates what consumers have left to tap. The only significant funds are pensions, which are generally hard to get ahold of and sitting in conservative hands.
Keep an open mind folks ...