Well obviously if everyone races to weaken their currency as fast as possible, that causes a lot of instability. A weaker currency hurts lenders and the wealthy, and drives up consumer prices, so it’s not some infinitely applicable strategy that can be endlessly pursued by everyone.<p>But the point is, the US dollar has been kept “artificially” strong for a good while now, which goes along with a structural trade deficit, current account deficit, low domestic savings rate, unemployment, rising prices of non-tradeable goods, and struggling US export industries. On the other side, countries with artificially weak currencies like Germany or China have had high domestic savings rates, trade surpluses, current account surplus, etc. This kind of imbalance builds up pressure over time, and isn’t stable in the long term.