Okay troll, I'll bite this time.
1. Taiwan is an island, and not physically part of China.
2. You say country, implying a nationalist framework. What constitutes a nation? Nationalists (an idea that's time is coming to an end) are pretty vague and change their criteria based on the situation because all they're really interested in is territory and resources. You will often hear them claim "shared history, language, and culture." Does Taiwan fit that bill? Only partially. Shared history is, like so many things, relative to geography. Though formosa has often shared sovereignty with the many governments of mainland China over the last few millenia, it has not always been the case, and it has certainly not been the case for tha last 60 years. Language? The language of the PRC is Putonghua, or Mandarin. The ROC: Cantonese. If you think that's a shared language, then you clearly don't speak either. Culture way to subjective for any definitive determination. Again, Formosa and it's people have always exhibited unique cultural characteristics. Anyway that's a weak argument from the people(nationalists)who persist in subsuming weaker minorities, like the Basque people, folks in northern Ireland, and don't even get me started on native americans.
The ROC has it's own nationalist government that's recognized by most of the other nations of the world, it's own economy, and it's own military that the PRC was unable to defeat during the revolution.
Now I realize that this has been a short incomplete little response, and that there are any number of arguments supporting any number of other positions, but the ultimate trump is this. The people of Taiwan ROC do not want to reconcile with the current Government on the mainland. When people want to be left the fuck alone, they should be left alone. God Damn greedy, power hungry fucking nationalist shitbags. Not that the ROC isn't the same kind of fucks, but that there's still contention over this issue only serves to prove that it's just the same old story. Greed and ambition. Now fuck off to politics or world news, this is the lounge.