To begin with, even if US is to completely ban the entire trade with China, it will be just a prick to an elephant...
Surely, the rest of the world will eagerly buy iToys, and stuff like cheap clothing – China is safe in that scenario. Not so much for US, biggest US exports to China are unsellable anywhere else. Surely, soybeans can be sold as animal feed, but it will saturate the market few times over.
Xi’s base of power is also not as stable as it seems. There’s grumbling within the party about him over reaching and the slowing economy is giving his opponents ammunition. If things continue on the current path, you may start to see open opposition to Xi’s policies, which will lead to questions about Xi’s leadership.