Also the folklore, "an ounce of prevention is worth a pound of cure".

PP is best applied to situations with the potential, not necessarily the guarantee, of widespread systemic harm and/or catastrophic failure from which recovery is exceedingly technically difficult, prohibitively expensive, or downright impossible - for example, nuclear war, climate catastrophe, global financial crisis, global pandemic of a novel and not-well-understood pathogen.

The "not necessarily the guarantee" is the hard part. Human judgement tends to be biased toward discounting both the odds and impact of occurrence of systemic risks that have less than 100% chance of occurring, but significant impact if they do occur. Especially when there are immediate costs to avoiding them, or immediate financial benefit to avoiding/externalizing them.

Thus it is often politically difficult for society and political leaders to apply PP to any particular systemic risk, until after it's happened and the odds of occurrence become 100% and the impact widely felt. Both the Great Depression and the Global/Great Financial Crisis are examples of this - prevention measures put in place after the fact. COVID19 as well.