Here's a The Week article from Yahoo News that argues the middle class is partly to blame for its economic woes. A factor the article does not mention is the increasing number of one-adult households.
As more people live as singles, or singles with children, they have substantially less disposable income than the households with two earners. They even have less income than many one-earner, two adult households which don't have to spend for childcare.
The increasing number of one-adult households is, I believe, a major factor in the hollowing out of the class structure, the reduction of the middle class.
