Your point is correct and important; I like to think of it as the proverbial "speak softly and carry a big stick".
There's however one key, pivotal change that happened during the wartime - scaling out the manufacturing and logistics. Primarily USA, and largely Great Britain and USSR, scaled out production of weapons, vehicles & materiel, subassemblies, and certain raw materials by factor of 10x or even 100x. Same with the related logistics. This was a huge undertaking[1], required high level of engineering, manufacturing, and managerial expertise. If people like GP only got into weapons & materiel production in the wartime, they'd still contribute greatly to the military effort.
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[1] building and relocating whole factories, rearranging production lines, and adjusting designs & manufacturing techniques for streamlining. Example, a ship was built in under 5 days: https://en.wikipedia.org/wiki/SS_Robert_E._Peary
There's however one key, pivotal change that happened during the wartime - scaling out the manufacturing and logistics. Primarily USA, and largely Great Britain and USSR, scaled out production of weapons, vehicles & materiel, subassemblies, and certain raw materials by factor of 10x or even 100x. Same with the related logistics. This was a huge undertaking[1], required high level of engineering, manufacturing, and managerial expertise. If people like GP only got into weapons & materiel production in the wartime, they'd still contribute greatly to the military effort.
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[1] building and relocating whole factories, rearranging production lines, and adjusting designs & manufacturing techniques for streamlining. Example, a ship was built in under 5 days: https://en.wikipedia.org/wiki/SS_Robert_E._Peary