For reasons? You want me to tell you the entire economic history of 3 countries in a HN comment? The US has no real industry except finance (well, and healthcare, and real estate (which is/was basically finance)), and our economy is only strong because of the petrodollar-created reserve currency. Take it away and we have a gaping void where an economy used to be.
Japan may implode if the US dollar collapses, due to the weird USD<->Yen cyclical debt scheme (yen carry trade) propping them up. If the world switches to the Yen to price oil this might not be so bad. They also just started moving away from negative interest rates and ZIRP, and BoJ may reach 1% interest at the end of this month. This is good for Japan, bad for US.
Germany is not doing great but they do/did have a strong manufacturing sector.