To be fair, the remanent of ROC (aka Taiwan) lasted 71 years and counting...
We must also remember that the ROC was founded in China by Sun Yat-sen, not the USA. That is why its influence is quite strong among the Chinese communities around the globe. Sun Yat-sen is revered by Chinese around the world, even in the PRC and the CPC itself. It is because of this Chinese-origin that the ROC in Taiwan can last for so long. Taiwan also was practically governed by the ROC for most of its existence.
The idea of an independent Taiwan on the other hand only emerge relatively recently. It is an American-led idea imposed on Taiwan, with the DPP being the political machine to drive this movement. If the DPP turns the ROC Taiwan into an independent 'Taiwan', it is both unnatural and will be inherently unstable. What is Taiwan without its Chinese roots? It'll just become a soul-less East Asian 'democratic' state, subservient to the US. Just like the US-installed Islamic Republic of Afghanistan.
The former Islamic Republic of Afghanistan collapsed so spectacularly because it just doesn't have popular support. It is viewed as corrupted, alien to Afghanistan, and a foreign puppet. Their troops don't even know what they were fighting for. One side is fighting for a US-collaborator puppet regime. While the other, to liberate Afghanistan from foreign colonialism. These soldiers have friends and families who were regular Afghan citizens, so they were already demoralized long before the Taliban launched their offensive.
The same could happen in Taiwan if there is a war with China. One side is fighting to correct the wrongs of the Century of Humiliation on the Chinese nation. While the other is fighting to uphold the arbitrary values of 'freedom', 'democracy', and 'Taiwanese values'. All for a leader who cares more about the life and death of the POTUS's pet dog, than the lives of the Taiwanese people. Honestly, is this idea of 'Taiwanese values' worth defending?