Robert Reich argues it is: http://www.nytimes.com/2008/02/13/opinion/13reich.html?_r=1&ref=opinion&oref=slogin
His basic point is that Americans have artificially propped up their standard of living by resorting to extraordinary measures over the last 30 years as wages have stagnated.
In brief: First families sent women into the work force. Then everybody worked more hours. Finally, everybody borrowed up to the eyebrows. There's nothing left.