The sheer scale of the U.S. economy is still hard to comprehend. In 1939, our military was virtually non-existent. Just a few years later, we had pushed the Japanese Empire back to their mainland and we were filling the skies of Nazi Europe with bombers, filling the oceans with ships and material and landing millions of troops on foreign soil with not only enough supplies for the troops but for the liberated refugees as well.
All this without a single successful enemy attack on our soil (Hawaii was not a state at that time). In fact, the war ended as we were just getting ramped up. If the war continued into 1946, we would by then have had triple the resources and if that wasn't enough, we would have tripled them again in 1947.
The atomic bomb made that pretty much unnecessary.
Good thing the EPA and endangered species act did not exist then!