I think you mean de jure. A mainland Chinese would not go to Taiwanese courts or abide by Taiwanese law, so you cannot say that most living in Qing China's imperial borders recognize the legitimacy of TW's govt.
Internationally, more countries abide by the PRC's One China policy than exclusively recognize TW, so it does not have international de facto legitimacy as well.
De jure... well, that would still be arbitrary. Go further back and one might consider the hereditary Qing successors to be the legitimate rulers. Or you might consider legitimacy to be conferred by the Mandate of Heaven, and by that reasoning China has never been more prosperous than the present in absolute terms, so then the PRC holds legitimacy.
Dejure is indeed a better-suited term than defacto. My mistake.
I was just trying to tell the history and articulate what happened. The meaning I intended was that the world and the US were allied with and recognized ROC. It is a case of "might makes right" where no court or treaty ever agreed to pass control, only war did.
Internationally, more countries abide by the PRC's One China policy than exclusively recognize TW, so it does not have international de facto legitimacy as well.
De jure... well, that would still be arbitrary. Go further back and one might consider the hereditary Qing successors to be the legitimate rulers. Or you might consider legitimacy to be conferred by the Mandate of Heaven, and by that reasoning China has never been more prosperous than the present in absolute terms, so then the PRC holds legitimacy.