I donate to GiveWell recommended malaria charities. Would I be correct in assuming that small donors aren't what Sanaria is interested in?

Not every country has a political myth about the fight against the Nazis. So one of them might eventually take up Hanson's suggestions.

Nuclear war would be very bad, but not truly an existential risk:

https://www.navalgazing.net/Nuclear-Weapon-Destructiveness

I did a quick search for any citations of Greg Clark, and didn't see any. There are other economic historians like him who have found not merely persistence of the status quo but robustness to disruptions to it.