submarines can disrupt shipping lanes vital for Chinese exports. Blowing up a few container ships and the global trade gets stunted to a halt. This will significantly damage both the US and China’s economies. The US has food and fuel, China needs to import food and fuel (and a lot of them came from America too), so the question is: who can survive longer?

Sorry but this a reddit tier analysis.

To begin with such an attempt by the US would come after some PRC blockade or kinetic action on Taiwan and as a result even if we assume what you say is credible as an anti-China strategy the answer to the question of "who can survive longer?" is by and far "not Taiwan". If the US doesnt attempt to actively break a Chinese blockade in a scale that matters or engage invading Chinese forces, so actualy engage in war in that theater, then Taiwan will capitulate in weeks and then its over. US cant get it back and them continuing to destroy the most important shipping lanes in the world after China already takes Taiwan is silly. For the effects of a blockade to even be felt by China, Taiwan would have to hold for over a year due to the size of China's stockpiles, which in and of itself is a highly questionable assumption given that unlike Ukraine, Taiwan is extremely reliant on trade for basically everything from food to fuel. If Taiwan falls in a few months which is a good case scenario for them, the blockade will likely not force China to relinquish control. If Taiwan doesn't fall in a few months, it won't be because of the blockade. A blockade cant be done with some subs striking rando ships. Its a completely lopsided resource drain for little to no immediate battlefield benefit which is what Taiwan needs. If Taiwan is successfully cut off from world trade, they have virtually no chance of lasting for very long and given deteriorating domestic conditions, they could probably be convinced to capitulate.

Lets talk self sufficency tho because you overstate chinese food and fuel dependance.

China produces 4.3m bpd, imports 11.4m bpd crude but exports 1.1m bpd refined. They can get abt 2-3m bpd from Russia. 400k bpd from Myanmar & Kazakhstan thru pipeline. Getting 6.5m bpd during an emergency is easily do-able.

Stopping half the flights, shipping & gas cars can cut abt 5-6m bpd of usage and in general gasoline/diesel usage can be reduced to minimal levels in such situation since NEVs are everywhere and they will be even more so everywhere with each coming year. Petrochem usage can be reduced through higher utilization in coal-to-chem plants + more imports over land. Food, Crude & refined products can be transported in over land through trains & trucks. North Sea Routes add additional shipping capacity - US would bring Russia into conflict if Russian tankers are targeted in their own water. China also has the option to increase the capacity from Russia but chose to not do it currently. If China bellived this was a problem they would have approved power of the Siberia 2 and other pipelines.

There is basically no way you can actually choke off Chinese economy through sea blockades of energy imports once its this far along in electrification of is transportation sector. And that's assuming you can choke off its energy routes to Middle East, which is dubious since any such effort would actually destroy Japan & SK + most of southeast Asia, who do not have the option of turning to EVs or coal chemical plants or importing via pipeline/shipping from Russia & Central Asia. Any real blockade would blockade ASEAN countries as well as Eastern Asian ones from the necessary energy imputs to have their economies functioning. You will be facing off against a southeast Asia who would also be eager to break off any blockade and work with china to get around it in any way possible in order to not collapse economicaly before even China feels the heat. You basicaly surrender the entire region to China and even make sure Japan and SK cant and dont join you in any action

There is also the feasibility of such blockade in the first place. Striking a couple of ingoing and outgoing comersial ships to China wont do shit to make the roots stop, which in the first place would collapse the economies of every signle country in the erea before china even feels it. To actually be effective you would have to manage an actual blockade of Malacca and likely more than just that since there are alternative, albeit slightly longer, routes due to the fact Indonesia is an archipelago. There exists the Sunda Strait just to the south next to Java and the Lombok Strait further east. If the Strait of Malacca is blockaded, it would be trivial for ships to divert towards the Sunda Strait or the Lombok Strait and completely circumvent the American blockade so for an effective blockade, the USN would have to blockade all three straits. That's a lot of resources the USN needs to divert away from the actual battle happening in the Pacific towards a blockade that won't have much of an immediate impact on the actual battle happening.

The USN will have to question if implementing three blockades in Southeast Asia is an effective use of their very limited resources against an opponent which will have a massive local superiority in forces.. The US needs as many assets in the fight to even stand a chance as is, there is little point crippling the world economy even more and putting South Korea and Japan on ticking time bombs by blockading three straits in and around Indonesia.

You also cant trivialize the amount of resources required to screen tens of thousands of ships carrying trillions worth of trade. Not as in "please report your manifest so we can carry out mutually beneficial peacetime commerce" but "physically verify every ship is carrying what it says and going where it says because they have a huge profit motive to lie." And that's not even counting all the ships who actually do dock in SEA, but whose cargos go to China by rail. The ships have no control over what happens to their cargos after they offload. The other option is what . Striking ships that may or may not be going to any random port or country in the erea. A logistical impossibility. Never mind that the US cant actualy track most container ships either in port or out in the sea if they dont want to be tracked. Let alone know which are china bound. Ship-tracking satellites do not exist. This is a fantasy. Its difficult it is to keep track of even just a ship in the vast open ocean, let alone thousands of them.

The US also just cant sink the ships when they are close to dock in China or leave china. The USN will be lucky to even have a few ships survive within stand-off ranges from the Chinese coastline. South China Se is pretty much a complete no-go for the USN considering the shallow waters reduces the effectiveness of submarine stealth, and the thousands of air and see sensors China has littered the erea with. The entire sea is well within range of China's absolutely gargantuan stockpile of AShMs and is close enough to Chinese air bases that the PLARF will have a massive numerical superiority to any potential USAF/USN aerial assets in the region. I highly doubt the USN will have any SSNs to spare for patrols of the straits around Indonesia to begin with when they will be desperately needed in the Pacific. The USN is already dealing with a serious hull shortage even during peacetime. I don't understand how people can expect the USN to have multiple SSNs available for something like a blockade when they'll need every little bit of help they can get in the Pacific. A very limited number of American SSNs who will already be tasked with the monumental job of surviving China's massive and extensive ASW network of ships, helicopters, submarines, aircraft and land-based sensors whilst at the same time finding, targeting and engaging Chinese warships will now also be tasked with implementing a blockade and attacking any and all vessels in the region, exhausting their already limited torpedo and Tomahawk supplies. This does not seem like a very useful way to utilise the only USN assets that have a higher degree of survivability within 1,000 km of Chinese shores given that these assets will likely have an actual amphibious invasion that they will need to stop.

Cause again sea trade in the erea wont stop just because the US randomly strikes 2,5 or even 20 containers they can fet their sights on out of the 1000 per day heading from and to China, never mind that it would be a completely self defeating endeavor in the first place.