Earlier quoted context omitted.
We're not talking about scaling out cloud deployments or something here. Building a military takes an incredible amount of lead time. If you don't have a strong standing military force during peacetime, you won't have one during wartime.
Utterly false. Prior to involvement in World War 2, the US had hardly any standing army and rather weak tooling industries (being wiped out by the Great Depression) and yet still managed to field like 2 million troops and vast amounts of weapons for allies in a very short period of time.
In the post WW2 era though, the increases in firepower and mobility made this point moot. A well orchestrated and timed advance could conquer a nation in days, nuclear weapons not withstanding. the Army's Active Defence doctrine post WW2 reflected this, recgonizing that in the era, a war would be won or lost in the first few battles.
Eisenhower reflected upon this in his Farewell Address. The warning regarding the "Military-Industrial Complex" was placed in the context that such a construct was necessary, but needed to be kept in check:
"Until the latest of our world conflicts, the United States had no armaments industry. American makers of plowshares could, with time and as required, make swords as well. But we can no longer risk emergency improvisation of national defense. We have been compelled to create a permanent armaments industry of vast proportions."