Correlation /= causation
The US economy expanded in the Post-war years despite a "monster" tax burden, not because of it. The United States economic growth was so great during this period because not because of high marginal tax rates, but because it was really the only player on the global marketplace. Western Europe, Great Britain and Japan were devastated during the war and were struggling to recover; the Soviet Union, Eastern Europe and China were basically non-entities in global trade.
In the US, low-paying jobs (farmwork) were being traded for higher paying jobs such as manufacturing in urban areas, and our consumer-based economy took off by feeding itself.
History has actually proven that economic freedom provides growth, not Gov't control.
For Example: Hong Kong
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"Dress cops up as soldiers, give them military equipment, train them in military tactics, tell them they’re fighting a ‘war,’ and the consequences are predictable." —Radley Balko