Here is the problem, Cutting off China is like Cutting off yourself from the world. Where will US and vassals get all the critical rare earth, thousands of other parts, machines and various manufactured goods?But the U.S. economy was not cut off from the rest of the world, not to mention the US was 100% self sufficient in all industrial goods at that time. Should a war break out over Taiwan, expect at least a trade embargo by U.S., EU, Japan, Korea, India, Australia, and some ASEAN countries. It would have all its assets in above mentioned countries frozen or seized. China would be fighting whilst isolated and cutoff, but its adversaries won’t be. Worse, countries like India could become opportunistic and start attacking Chinese merchants in the Indian Ocean. Of course, a victory over Taiwan could alleviate these isolations, but most Chinese citizens would kiss goodbye to whatever is left of China’s trade with richest countries in the world. It would probably take decades before western countries would come to terms with a unified China.
Europe could not even cutoff Russia and had to import Russian oil and gas which is a commodity and there were alternative producers. China produces things that no one else does.
So, no. I don't think anyone is commiting economic suicide by trying to cut China off wholesale. There will most likely be selective action that those countries can tolerate.
As for raw materials import. China can import from Land from Russia. Russia pretty much has every raw material. China can also get raw materials from its neighbours transhipped. Finally, we are talking about a hypothetical scenario of China fighting a 4-5 years war with 5-6 million soldiers. They will be building up a massive navy. So, I don't think anyone can blockade China with that kind of naval power.
Finally, China's land based fighters, bombers, and anti-ship missiles have very long range. DF-26 can sink Ships in the Indian ocean from China's own border. Let that sink in. So no blockade is enforcable against China.