I think American culture is deeply disoriented in regard to assessing standards of living. The basics of life — having a home in a safe neighborhood in reasonable proximity to one’s work, the choice of having a one-income household, having time and energy to invest in family life and parenting or in personal interests or in reflexion — are now beyond the reach of many people. However, luxuries — such as hi-fi home and portable stereo systems, home theaters, computers, multiple luxury cars, fine food — these items are relatively cheap.
Any comparison of how the middle-class is doing now versus ten, twenty or thirty years ago that only adjusts for inflation without adjusting for the relative costs of basics and luxuries, or considering the number of hours worked per household (or better, the amount of free-time available to members of the middle-class) is barely looking at the real issue.
The crisis of the middle-class has less to do with how much money each household has, and more to do with quality and sustainability of the middle-class life.