"spending by households on many of modern life's 'basics'" The article factors in auto payments as a basic, but not gas prices - which have risen for people since the 1950s. It does not factor in the increased amount of money going to their HMO (some of which is then sent as a dividend to GMO stockholders, there's a racket...) It also does not factor in that people have to spend more on their own training and college education just to make the same wages as someone without these things could make at a factory in 1950. You would be correct in saying food prices have fallen in the past 60 years, but their claims that the middle class now has more disposable income is false.
The fact which they can not deny is that inflation-adjusted hourly wages have fallen since the early 1970s. Many of the points they make are sophistic. They do make the point that commercial airplane travel has improved since the 1970s, but how often does the average middle class person use that? Most of the people I know who fly regularly are made to do so by their jobs and are usually unhappy having to spend so much time away from home in order to make a living.
"spending by households on many of modern life's "basics"—food at home, automobiles, clothing and footwear, household furnishings and equipment, and housing and utilities—fell from 53% of disposable income in 1950 to 44% in 1970 to 32% today."
There's a reason why the middle class today can buy so much MORE stuff, it's all much cheaper. The article is saying people are not richer, but the quality of life is not significantly different for the middle class then it is for the rich (the same access to long life, short travel, etc...)