The problem with your statement is that you’re only comparing Post World War II to Pre World War II. After World War II the country was once again a place full of people that were confident in their ability to tackle the challenges facing them, and confident in their place in the world. There were also GIs returning to the country that hadn’t been able to spend all of their pay and thus had savings.
As the other poster mentions, the US Savings rate was also much higher.
But what is being ignored is the fact that the “growth” rate wasn’t anything compared to the growth rate from 1800 - 1913.
Then there is the fact that another contributing factor to the apparent “Growth” was the devaluing of the currency, a move that effectively increased the “size” of the economy in dollar denominated terms with out actually doing anything to alter the real size of the economy. This happened when FDR dropped the Dollar from 1/22 troy oz of gold to 1/35 troy oz of gold, essentially doubling the number of dollars that the production of the economy was worth.
Essentially, FDR manipulated the US Currency to make .4 Billion Dollars appear out of nowhere for every real 1 Billion dollars in existence. There was no increase in production, or true growth in the economy.
In fact real economic growth Post World War II has been drastically slower than Pre 1913 Economic Growth.
From 1800 - 1913 Years with Real (Inflation Adjusted) Economic Decline were
1815 with -1.97% growth
1816 with -3.62% growth
1817 with -0.86% growth
1819 with -1.37% growth
1838 with -0.10% growth
1860 with -0.68% growth
1861 with -0.20% growth
1864 with -0.79% growth
1866 with -6.65% growth
1867 with -0.44% growth
1875 with -0.16% growth
1884 with -2.05% growth
1893 with -5.02% growth
1894 with -4.27% growth
1896 with -0.64% growth
1904 with -1.92% growth
1908 with -9.31% growth (right after the banking “crisis” of 1907)
1910 with -0.66% growth
from 1913 on the years of negative real growht have been
1913 with -14.79% growth
1914 with -7.52% growth
1917 with -0.11% growth
1919 with -10.07% growth - Post World War I Slow Down
1920 with -2.54% growth - Post WWI Slow Down
1921 with -6.79% growth - Post WWI Slow Down
1930 with -9.70% growth
1931 with -8.02% growth
1932 with -14.45% growth
1937 with -17.19% growth
1945 with -0.75% growth
1946 with -8.22% growth
1947 with -3.92% growth
Of course part of the slow down from 1945 - 1947 was shifting from military production to consumer production
1954 with -0.23% growth
1958 with -1.38% growth
1970 with -0.42% growth
1980 with -4.14% growth
1982 with -1.96% growth
1991 with -0.85% growth
and 2008, which I don’t actually have the decline in real economic growth for, but have seen estimates of -6% just for 4Q, 2008.
From 1800 - 1913 there were also 47 years with real growth above 5% compared to just 31 from 1913 with the last year at which economic growth was more than 5% being 1984.
In short the post 1913 Economic growth pales in comparison to the pre 1913 Economic growth during which the economy grew from .47 Billion Dollars to over 44.93 Billion dollars or 95.56x. All of this growth was accomplished with negative inflation of -16.76%, or deflation (increase in the value of money.)
From 1913 on the real growth has been a comparatively anemic 16.34x with total inflation of 2,106.66%. In short it can be concluded that the United States has been suffering from politicians and a Federal Reserve that have collaborating to use mismanagement of the money supply to mislead the public into believing that the economy is 22x bigger than it really is (625.72 Billion in 1913 dollars vs 14 Trillion in inflated 2007 dollars), and have used this fake appearance of growth as an excuse to continue turning what was once an Individualistic Republic into a Socialist Oligarchy.