I believe this ignores the ripple effects of a crashed US dollar. Unfortunately world economies are intertwined in a way we've never seen before.
I don't think either the Euro, USD, or Pound could collapse without dragging down the others indirectly. There's a reason to 08 crash was felt worldwide.
Don't get me wrong it would be the worst for the United States and any nation that fixes their currency to the dollar. But probably quite painful to downright disastrous for many other nations.
Of course all of that happens anyway if Trump does the worst of what he says.