If you retool all of that to suddenly do something else, than you will be missing something else.
Because it's not like these 50+ nations with over $40 trillion in GDP are just sitting there and wondering what to do with all of that productivity, they are already plenty busy doing those things that got them all that GDP, the things they are good at.
That's why it's not really a "straw man", as the original argument implies globalized supply chains that emerged out of a given supply&demand could be artificially transplanted and rebuild in "the West", however that's even defined, to somehow reverse the reality of globalization.
Except that it is a straw man. This "childish" nation that seeks to thrive with no foreign trade ("in complete isolation") is a fiction inside your head that you're sharing as a target for your argument. It doesn't exist except as a straw man.
> The idea that a single country could emulate that, in complete isolation, is bluntly said childish.
Who is this “single country” straw man you are referring to? The western world is comprised of 50+ nations with over $40 trillion in GDP.