I have prepared for economic collapse. I studied what actually happens when national economies decline/collapse. Even though I know that most/all wars are economic in nature I could not/would not consider preparing for a real war. Preparing for war is different than preparing for economic and social collapse.
With that said, I don’t think I have the economic resources to prepare for WWIII. Most of my preps are for hunkering down and now I will have to consider becoming more mobile should the need arise. Establishing a bug out location.
It is an interesting topic: Prepping for Economic Collapse vs. WWIII.