"America has made it diplomatically very clear that Taiwan stands alone if she declares independence."
Again, you don't know what you are talking about.
The Chi-com appeasers at foggy bottom can spit and fume, publicly, all they want about Taiwan "provocations", while they remain silent about China's constant provocations.
The fact that we don't tell them to shut up is simply to let their diplomatic language try to keep things appearing balanced and unchanged. The fact is that the only thing, from a U.S. official policy point of view, that can change that balance is a military offensive by China.
The fact is that the official U.S. policy does not, acknowledge Taiwan as a province of China; it is officially uncomitted to a position on that matter; officially we do not say we agree with China's position; we say, officially, our position is that the definition of that issue MUST be worked out by China and Taiwan and that it cannot be worked out by military force. Our official policy is agnostic on the issue, and the other side of that agnostic position is that the dispute MUST be resolved without force. That position is not predicated on ANY NON-MILITARY action that Taiwan takes.
As far as Japan and South Korea are concerned, again you are wrong. Their agreements with us include the clear assumption that an attack on Taiwan will not be tolerated, and will be responded to with our defense of Taiwan. That is not wishful thinking on my part, that is U.S. strategic doctrine. Taiwan will not "stand alone" if it is attacked, no matter what declarations it does or does not make. Again, that is U.S. policy.
It is not a matter of defending or rejecting those declarations of Taiwan's, it is our policy to defend the position that the issue CANNNOT be resolved militarily, and any attempt by China to resolve the issue militarily will result in our seeing all our agreements with China as null and void.
"In the long run" it is not a given when there may yet be a "free" mainland China (if ever); but there is no question that that hoped for condition will not arise as long as the dictatorship remains in control there.
When would Taiwan happily and voluntarily join its cousins on the mainland, in some type of political union? When the dictatorship no longer rules there and not a moment sooner.
China is not ignorant that its prosperity depends on trade with us, while U.S. and other nations' manufacturers' have all the rest of Asia and eventually Africa and elsewhere to place their lower-cost manufacturing, if they want to; they are not dependent on China, it is simply a choice at the moment.
However, that choice is dependent on the continued belief in the myth that China is reforming and not just economically but politically. The maintenance of that myth will end the day a Chinese dictatorship attacks Taiwan; as will all of China's economic benefits and ties to US.
China knows (the world knows) that while "independence" or anything else can mean allot to Taiwan, none of the advantages of independence for Taiwan are any real and actual threat to the nation of China. The only thing an independent Taiwan threatens is the loss of public respect that the rulers would have, on the mainland, for their continued denial of political freedom on the mainland. The dictators use nationalism to hijack it in support of their desire to expand the imposition of their dictatorship to Taiwan. The entire issue is not about any real threat that Taiwan poses to the nation or people of China. Its the threat to the political rationale for the dictatorship. That, not any moral or security issue relative to the sovereignty of China is what concerns the dictators and why the Taiwanese continue to oppose any union with China. If China had a democratically elected government with full and guaranteed political freedoms, there would be majority support for some political arrangement with the mainland. Without that, there is no such majority on Taiwan and less and less so likely over time.
The longer political reforms remain elusive in China, the greater the pressure and the greater a majority for independence on Taiwan will grow.
You can type all that stuff as often as you like, but it won't make it true. The name "Wuli" is very close to "Wulu," but the latter means "deer in the fog." I think you may be in the fog.