!945-1948 started to look ok as people started buying cars after the war, but it soon stumbled, which was one of the reasons that congress allowed us to be dragged into Korea.
By 1955 it was clear that we were headed down at a constant rate. Foird and Chrysler were in trouble, and Studebaker/Packard, as well as wyllys were essentially done. Aerojet dropped the Crosley line, and Kaiser also bailed out.
Taxes kill economies, and the 90+% taxes on producers were a huge anchor dragging everyone down.
I have never heard that post war America was a period of economic despair.
“As the Cold War unfolded in the decade and a half after World War II, the United States experienced phenomenal economic growth. The war brought the return of prosperity, and in the postwar period the United States consolidated its position as the world’s richest country. Gross national product, a measure of all goods and services produced in the United States, jumped from about $200 thousand-million in 1940 to $300 thousand-million in 1950 to more than $500 thousand-million in 1960. More and more Americans now considered themselves part of the middle class.
The growth had different sources. The automobile industry was partially responsible, as the number of automobiles produced annually quadrupled between 1946 and 1955. A housing boom, stimulated in part by easily affordable mortgages for returning servicemen, fueled the expansion. The rise in defense spending as the Cold War escalated also played a part.
After 1945 the major corporations in America grew even larger. There had been earlier waves of mergers in the 1890s and in the 1920s; in the 1950s another wave occurred. New conglomerates — firms with holdings in a variety of industries — led the way. International Telephone and Telegraph, for example, bought Sheraton Hotels, Continental Baking, Hartford Fire Insurance, and Avis Rent-a-Car, among other companies. Smaller franchise operations like McDonald’s fast-food restaurants provided still another pattern. Large corporations also developed holdings overseas, where labor costs were often lower.
Workers found their own lives changing as industrial America changed. Fewer workers produced goods; more provided services. By 1956 a majority held white-collar jobs, working as corporate managers, teachers, salespersons and office employees. Some firms granted a guaranteed annual wage, long-term employment contracts and other benefits. With such changes, labor militancy was undermined and some class distinctions began to fade.”
http://www.let.rug.nl/usa/ECO/1991/ch3_p12.htm