It sounds simple to start producing to sell to others other than the USA, but they are the ones who buy the most on the planet, so selling to those who do not consume is not easy. CHINA does not buy either, it only sells. There is no other country with enough capital to cover this, nor is there a need in the market for which countries have a product to buy, nor has the USA let its system die, it increasingly makes moves to strengthen its currency, when it feels a possible threat, at the moment at a practical level there are no real solutions or ones that can be executed.
No it is simple, it just takes time to adjust. The initial sales would be lower, so production falls, but as the rest of the world would effectively start increasing its own possibility to purchase, it would rise again. The US is the largest single consumer, but not if you factor in the rest of the world as a whole. The rest of the world could increase consumption by about 6% and cover the US. And, it could be partly financed in the short term by appropriately taxing the US companies where they earn their money. Cutting off the US of both cheap capital inflows that drive their stock prices and dividends, whilst also cutting off the supply of all the goods that the US has been getting for cheap, because the global companies want access to the largest single market.
I agree that it would be a very good idea but I do think it's much harder than you think... purely because shareholders demand constant growth and so if a company has 20% of its market in the US, any CEO that suggests dropping revenue by 20% won't last long enough to have that 20% replaced by other countries.
Private companies have a much better chance, but I still imagine it'd be hard for them to step away from the US market and allow their competitors to pick up the slack.
Unfortunately, as with everything, capitalism ruins this fantastic idea.