By definition if you isolate a country from the world it would be more self sufficient that very moment than it is the moment before it is isolated. Isn't that obvious?

Agreed self-sufficiency isn't the best term. But if I were to rephrase it, let say that self-sufficiency in terms of the quality of life - US would be in much better shape than Canada. Canada has _significantly_ much more to lose than the US.

Sure, but you don't need that hypothetical to explain that. The USA produces and consumes more goods than Canada. Overall people are resilient and able to survive such disruptions. I'd rather be sovereign and poorer than whatever kind of second-class "American" status the USA would grant us forcibly annexed Canadians. To me that's more to lose than every loonie in my bank account.