Your assumptions make no sense. They can switch to a metal that almost no one accepts as payment anymore but they can't accept Bitcoin? That just doesn't make sense. Why is the assumption that metals would be what everyone defaults to in a digital world? Your thesis is that suppliers in a global economy will choose to fuck around with metal coins instead of adopting a digital currency that is already being used globally. We already did that once and ended up with fiat. People didn't have Bitcoin as an option.