Only half of the incidents listed were actually full-scale wars (WWI and II). The other two incidents are an oil shock and a pandemic.

The commonality between all four of these incidents is that they correspond to severe supply shocks:

- During WWI and WWII, industrial supply was rerouted by force to the war effort, leaving normal consumer demand unfulfilled.

- During the oil crisis of the 70s, a critical energy input to the American economy massively increased in price due to sanctions placed on America.

- During the COVID-19 pandemic, a significant chunk of workers were paid not to work, as a form of deliberate supply destruction to avoid the spread of a novel coronavirus.

In a "normal" economy, supply is flexible enough that you can print money and nobody even notices. The supply curve is smooth and gradual, so prices only rise a little. When supply is constrained, however, prices rise to whatever value is necessary to curtail demand, because they have to. The supply curve is a brick wall.