I'm not sure we disagree on capabilities.
The difference in comparing to WWI and WWII is that in those conflicts the situation was such that the losing side could be entirely conquered or forcing a capitulation.
The US has no means of actually conquering china and forcing a capitulation would require nuclear weapons. So the situation is similar to that of the cold war where the tensions were quite high and possibility of direct confrontation always present, but neither side was willing to risk nuclear war.
So this is the dynamic that I think is the best reference frame, in that proxy wars can be fought all over the place but pushing too directly and too forcefully may solicit nuclear escalation and so there's is extreme reticence.
For example, that is a central hypothesis to my analysis of the Ukraine conflict, that US / NATO could have supplied far more damaging systems and equipment far earlier that could have had a far greater chance of actually pushing the Russians back to their borders, but wargaming that out super duper probably results in the use of nuclear weapons. For, US / NATO could have provided all the cruise missiles, longer range air defences to strike aircraft, even F-35 and F-22's and diesel submarines and so on, if they "really, really, wanted", and most importantly a massive scale up of drone production and supply using that larger economic power even only of the US, Ukraine to win.
So my basic contention is that it would be a similar "not too much" stable point for US-Chinese relations. — boethius
This is mostly tying back to subjects of "limited war vs. full-scale war" which I think enough has been said about.
I instead wish to focus my reply on the more concrete aspects of a US-China conflict, as per the other portion of your post:
Implode is a strong term.
Obviously China would still be there with enormous production capacity and problem solving capacity, so China would then work on getting around the blockade. — boethius
Other neighbouring countries can be traded with by train [...] — boethius
The Chinese may be able to produce food, power and manufacture enough goods to maintain a non-critical standard of living, but modern economies cannot run on their own, not to mention the fact that China has a huge overseas trade network which would be severed overnight, together with all its foreign and domestic dependencies.
What I'm missing in your post is the fact that China's land access to foreign markets is very limited under the conditions we have discussed.
Trade with Russia is in all likelihood safe through Kazakhstan, Mongolia and (if all else fails) a corridor near Vladivostok.
Then it could probably maintain trade with
some South-East Asian countries, though this region will likely be in chaos if this scenario were to come to pass.
But this is small fry - a fraction of what China has access to now, and a fraction of what China needs to stay a geopolitical contender.
Overland trade to India must pass through Pakistan or Bangladesh.
Trade to the Middle-East and Africa must pass through several unstable Central Asian countries and then pass through Iran, which will likely be at war with the US and Israel.
Trade to Europe must pass through Russia.
[...] China can send ships into neighbouring territorial waters and the US would need to then commit acts of war on those countries also. — boethius
These are not wartime considerations, in my opinion. What power does Vietnam have that it's going to enforce its territorial waters against a US coalition?
The US is already bombing neutral shipping for carrying Russian oil, and I believe the most recent attacks took place in Turkish waters.
Assuming it does not go nuclear but China sort of "take it" they could anyways inflict costs on the US due to the lethality of missiles, China can keep US ships fairly far from the Chinese coast, certainly outside Chinese territorial waters, and then continuously run the blockade with a civilian ship and an escort. Chinese would be then within it's right both morally (for most people in the world) and also in international law to run the blockade with escort and then return fire. These ships could be unmanned.
So even if China cannot entirely break the blockade and defeat the US navy it can in this iterative process inflict costs with continuous improvement to the strategy.
So it becomes a case of how long can US maintain the blockade, to what extent it could contain blowback in the rest of the world for a clearly illegal blockade. Other countries may send their merchant ships to China, daring the US to sink them.
All of these factors would make things very messy and very quickly so my main issue is not so much that such a blockade could not be started but what is the endgame?
Navy ships are expensive and if the US is blockading China and China is regularly running the blockade and manages to sink ships, even a really nice ship ... the response can't just be nuclear (otherwise the correct strategy is just to nuke China to begin with), and once the US starts losing ships it's very difficult to engage in a war of attrition at sea (you sort of need either overwhelming control or then to leave, as we saw recently in the Red Sea even moderate costs inflicted by the Houthis caused the "Coalition of the whatever" to leave).
Now, without nuclear weapons then it would certainly be within the realm of possibility, if not super likely at this point, for the US et. al. to galvanize their populations into total war and go on a world conquest campaign and truly physically contain China. I'm not entirely confident what would actually happen in such a hypothetical but certainly conceivable.
However, with nuclear weapons, push too much on a nuclear armed state and at some point their going to resort to nuclear weapons use. — boethius
Apologies for being blunt, but I think your idea of what a naval war in the Pacific would look like is not very realistic, and I understand now why you believe China is less vulnerable than it actually is.
To illustrate my point, I'm going to describe to you the path a Chinese merchant (or naval) vessel would have to take, in order to do anything.
1. A ship must leave port, which under a blockade will be mined and surveilled by submarines.
2. If a ship manages to leave port, it will then be subjected to submarine interdiction and long-range US fires from naval bases all over the area.
3. If the Chinese use their missile arsenal to keep US fleets at bay, and a large naval escort to counter submarine threats and intercept missiles, they can try to make a dash for the open ocean.
(Note that chokepoints like the Strait of Malacca, other Indonesian straits or the Sea of Japan will be essentially insurpassable due to mines, submarines and naval sea and air assets, in addition to land-based installations.)
4. To get to the open ocean, the Chinese fleet must then pass through TWO island chains which will provide similar obstacles as the previously mentioned sea straits. The fleet will also have to leave the Chinese missile umbrella as it travels further from the Chinese mainland.
5. In the unlikely event that the Chinese fleet survives the gauntlet, it has now reached the open Pacific, where it will be no match for the US navy.
6. But where would they even go from there? Would they cross the Pacific to do trade in South America? Would they sail around Cape Horn towards Europe and Africa? Would they sail around Australia? Hopefully you start to see the problem.
And this strategy is not overly costly for the US at all. All of the capabilities and assets have been in the region for decades, neatly stashed away in US bases waiting for a job. The US also has several allies in the region, and they are strategically very well situated.
I don't see a concrete plan for how the Chinese can counteract these massive threats.
It can use its missile arsenal to impose costs on the US when it sails close to Chinese shores, but there is no onus on the US to do so.
At best, the Chinese can try to achieve something on the Korean Peninsula or Taiwan, but at that point we're probably already talking several years of full-scale war, the primary cost of which would not be borne by the United States.
Meanwhile, this base-line scenario already seems to me catastrophic for China as a great power, and in my view would already suffice to achieve US strategic goals of re-establishing global primacy by knocking down China.
The nuclear dimension is of course more difficult to predict, but ultimately nuclear war is something neither the Chinese nor the Americans benefit from.
I also think China is unlikely to resort to nuclear weapons if the Americans do not threaten mainland China with an invasion, which, as discussed, they really don't need to do.