What will happen to the world when we let our governments run themselves into the ground?

When considering the current economic and social structures of America and the developed world, and the projections of our (America’s) inevitable implosion, I sink into a dark state of depression and empathy for those who depend on us, so please answer precisely and give just be true to yourself! With our economic fallout we have and will continue to, I believe, fall short on vital purchasing from world economies as well as the aid(water, food, education) that we have been granting around the world.
To be concise I will phrase my question strictly based around that: If or when the American/World economy goes belly up, where will the hardest hit areas be and what will happen there. Also, what are some methods to promote social change that could help to avoid this (either new or historically applied methods.)