No, you ARE wrong. Everything built in the United States survived the war. . . it's called industrial infrastructure built for the war effort that was put to work in other ways post war. The depression WAS ended by WWII as the unemployed were put to work manning the army, staffing the building of the industrial infrastructure to build millions of rifles, handguns, bayonets, 2.5 million machine guns, 2.4 million trucks and jeeps, over 180,000 tanks and self propelled guns, 325,000 military aircraft, 22 aircraft carriers, 8 battleships, 48 cruisers, 349 destroyers, 420 convoy escorts, and 203 submarines, as wells as hundreds of freighters. . . all in five short years. NONE of the plant, equipment, shipyards, and most of all skilled, trained hardworking labor in the USA was destroyed by WWII.
In addition, in Europe and Asia, the old infrastructure, out-moded, antique, no-longer able to compete, was often conveniently removed by twenty minute—in a couple of cases, twenty second—demolition efforts courtesy of the allies, making way for much more modern, more efficient plants and equipment that would in a very short time make them economic powerhouses competing with those who thought they had vanquished them. Hiroshima, Nagasaki, Dresden, all became amazing industrial centers when rebuilt.
All of this broke the back of the entrenched depression.
The Depression ended with the end of FDR, at the END of the war.
To be precise, I would say it was a national will to build out that infrastructure in defiance of the "progressive" theory and practice of the day that ended the Depression - and our current Depression will not end until we develop some similar motivation to defy today's progressives and set aside their economy-killing schemes.
No, that is a complete myth.