US trade GDP is 27%. Most major OECD countries' trade GDP is 60%+. PRC is relatively well insulated at "only" 37%, closer to US which is generally considered as self-sufficient. Covid19 demonstrated even worse disruptions are survivable short term. Essentially every major trading country is going to lose more than PRC if they support a US led blockade, which isn't guaranteed. Almost no one wants the US to unilaterally disrupt global trade over TW. Thanks to wolf warrior counter sanctions, even non-US sanctions aren't guaranteed. As for copper, there's a strategic reserve, and again PRC will be on a time limited war economy. PRC currently has 80% share of rare earth and a monopoly on processing that will take decades to erode. Again, it hurts everyone else more. As for imports, while PRC imports a lot to sustain the normal economy, PRC also produces enough for a massive war economy. Domestic petroleum, iron ore production, RE + reserves is sufficient to field assets multiple times the size of USN. The US simply can't starve the PRC strategically like Japan.

BRI hype is mostly theatre / exporting excess infra capacity, it will take decades to cultivate alternate routes and still won't rival shipping via water. The numbers don’t add up. Almost every country with PRC supply route is subject to US bombing in full scale war - US think tanks already proposed landing missiles in SCS islands even if against wishes of SCS nations if shit hits the fan. The US will have no problem bombing infra in the Stans to contain the PRC. Only viable secure route is via Russia due to nuclear deterrence but again land routes are simply insufficient longer term alternatives.

Ultimately US-PRC confrontation / PRC breaking US containment for good will be decided in the waters. In case of the USN attempting a blockade on PRC (legally an act of war), the battles will be decisive, with existential consequences. PRC has options to undermine blockade like bait the USN into defending Japan / Korea, or counter blockade of everything in the 1st island chain from the US. Or destroy all east Asian semi supply chains which set back US manufacturing for decades. Or massive crippling cyber attacks. There are multiple domains of MAD, not just nuclear that makes prolonged confrontation unfavorable. PRC is not just going to sit there and take it.

Also, even if the US sinks the entire PLAN fleet, PRC may still force pyrrhic costs on the US. Every ship in the USN fleet has to dock eventually, including nuclear powered, PRC has enough conventionally tipped ICBMs to hit them without complex kill chain considerations. Destroying the oilers and replenishment ships while in port and the nuclear USCGs that’s hiding out at sea become useless. People aren't fathoming scenarios where both sides lose terribly, but ultimately the US loses more because she started so far ahead. A US unable to honor her global security commitments because she lost so much assets to the PRC loses her hegemony. Is TW worth that? All interest calculus points to no. Especially considering PRC is much easier to contain once she takes over TW. Most countries in the region will become MORE willing to US assets to contain PRC once the TW conundrum is resolved, because they want to deter PRC, but not at the cost of being dragged into war over TW.