The Wages Of Alan Greenspan's Sins

Probably the best short description of what I believe happened to the economy in the 2000s, in today's WSJ:

The 2001 recession might have ended the bubble, but the Federal Reserve decided to pursue an unusually expansionary monetary policy in order to counteract the downturn. When the Fed increased liquidity, money naturally flowed to the fastest expanding sector. Both the Clinton and Bush administrations aggressively pursued the goal of expanding homeownership, so credit standards eroded. Lenders and the investment banks that securitized mortgages used rising home prices to justify loans to buyers with limited assets and income. Rating agencies accepted the hypothesis of ever rising home values, gave large portions of each security issue an investment-grade rating, and investors gobbled them up.

But housing expenditures in the U.S. and most of the developed world have historically taken about 30% of household income. If housing prices more than double in a seven-year period without a commensurate increase in income, eventually something has to give. When subprime lending, the interest-only adjustable-rate mortgage (ARM), and the negative-equity option ARM were no longer able to sustain the flow of new buyers, the inevitable crash could no longer be delayed.
Add that to the constant, junkie-like need of the big financial institutions to continue that cheap credit fix, and the stage is set for a whopper of a withdrawal in which the privileged get the buzz, and we all share the pain.