True. But... Here's the problem for China.
Notice all the critical straits Chinese produced goods have to be shipped through. Oil and food come back. Every one of those checkpoints we have the ability to gain and hold, even at the same time. China's growing Navy doesn't have expeditionary, blue water forces, yet.
You can't eat iPhones, plastic ware, TVs and appliances.
Basically, they import food and export nice things everybody wants.
The USA would have a critical component disaster, to include medicines and medical supplies. However, we do have the ability to make stuff here, it's just so much cheaper to make stuff in China and ship it here.
A billion people get mighty hungry. And modern economies need oil, and China still gets most of theirs from sea.
Lastly, the Chinese do NOT have a blue water Navy, nor the ability to project power beyond 1000 miles from their coast. I've already explained the risk they take if they use ballistic missiles, with nukes or conventional warheads.
How long will last I do not know, but currently, only the US has the forces, men and materials to invade another country over sea and land. Tawain is doable for the PLA, but not if we and the Japanese intervene.