China will stop subsidizing the US when they have the ability to run a closed economy.
They have been doing this to build out their infrastructure and all they have to do is start paying the workers a wage that will allow them to purchase the goods that they produce.
This is not going to continue forever.
It is all mute anyway because of the depletion of cheap energy.
The only reason that the US is still in control is because of military superiority and that is it.

"moot"