There are a bunch of scenarios where the US becomes an unpleasant place to be (eg 1860s, 1930s, 1970s) without collapsing, and where specific other places will have problems but probably won't be terrible, and for a given bundle of preferences, resources, etc. might be better. Global thermonuclear war isn't the only risk. Even if you just took the covid situation and scaled it up to 10 years duration and 10x more lethality, I'd pick Argentina over most of the US (although rural WY, MT would be fine too).