I don't think things are so straight forward because everything is connected in ways that are sufficiently complex to defy any sort of straight forward thinking; when you change one thing, 10 other things change and in ways that will invariably end up with completely unexpected outcomes. For the most straight forward example - those things that are exported are not just buried, but end up being used in various processes. And China itself is also heavily dependent on imports, importing upwards of $3 trillion in goods and services. When your exports are no longer available, you may soon find that neither are your imports, and suddenly everything starts breaking.