There is a very sudden shift though - those options have existed but not generally been seriously considered. The US was seen as a bastion of stability and while sanctions could drastically impact a country's ability to trade due to the reliance on US currency exchange it has arguably been used relatively scarcely.
The change is that suddenly the US isn't a bastion of stability and having an independent trading currency could ensure more internal stability for other nations.
The U.S. is as stable as it gets. It has been one continuous republic and has 250 years of legal stability and a history of paying its debts. It has 4.2% GDP growth, with the largest economy in the world and growing.