Their argument is that, by definition, it can’t be a world war unless all economic surplus is dedicated to war purposes.

I tend to agree with both of you, and that by extension, we will never see another world war unless society as we know it collapses significantly.

I don't think you are using standard definitions.

> A world war is an international conflict that involves most or all of the world's major powers. > https://en.wikipedia.org/wiki/World_war

> Total war is a type of warfare that mobilizes the totality of national resources to sustain war production, blurring the line between military and civilian activities and legitimate attacks on civilian targets as part of a war without restriction as to the combatants, territory or objectives involved. > https://en.wikipedia.org/wiki/Total_war

It does so happen that the two world wars were also total wars.

Well first off I think we were speaking colloquially. But secondly, I think unless certain powers cross some threshold where they’re undeniably engaging “total war”, they’ll use wishy-washy terms like “special military operation” (Russia) or “armed conflict”. That’s also not to mention proxy wars (Syria) or even non-violent acts of aggression against sovereignty (Hong Kong).

In other words, “total war” is a necessary ingredient for a “world war” these days or you’ll have all of these countries claiming they’re not actually at war.

Things have changed since I was a kid. We've gone from saturation bombing and dropping nukes as the big kahuna to being able to do point assassination strikes.

Topical the Israelis just killed Khamenei.