[DoughnutHole]

You don’t just press a button that says “war economy” and then everything turns out fine. You drive massive inflation, weaken consumer markets, take on massive debts and eventually run out of young men.

Pretty much every nation bar the US was on the verge of economic collapse by the end of WWI (and Russia’s did). The financial burden of two world wars killed the French and British empires. Germany’s WWII war economy was totally unstainable and the USSR’s was bankrolled by the US lend-lease program.

It’s not a panacea - it’s just what you have to do to drive enough military production to sustain a near-peer conflict.