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Obviously that depends on the amoount of people and how far something has to fall, but it can happen. Other things will fill the void. Same goes for nations if you look at former superpowers like France, Spain or the UK. Everything can break.
And I say this as an European.
Don't overestimate the US military industrial complex. Their biggest skill is lobbying, and selling massively expensive 'super weapons' that are too expensive to use.