US Militarization and GDP

I am currently reading McNally's Global Slump: The Economics and Politics of Crisis and Resistance. The author makes the claim that "When the war commenced in 1939, the American economy was half the size of Europe, Japan and the Soviet Union together. But after its wartime boom, as factories churned out steel, aircraft, tanks, electrical goods, bombs and more, it emerged by war's end as larger than all these others combined. American-based manufacturing accounted for fully half of world output at the end of WWII."

I hadn't realized that WWII had been so great for the US economy, so I set out to verify McNally's claims. I found a spreadsheet of historical nominal GDP by country estimated back to year "0" at the University of Gronigen's Maddison Project. Presuming the validity of the data, it indeed appears that the vast US militarization for WWII pushed the United States far ahead of other national competitors. The three lines I plotted were: United States, non-US Allies (UK, France, Soviet Union, China, Belgium, Netherlands), and the Axis Powers (Japan, Germany, Italy). No wonder General Eisenhower felt the need to warn the future US about the growth of the Military-Industrial Complex--he recognized the economic value and feared we would ourselves become another Fascist state, the same as what we had just defeated.