OP is getting dogpiled for pointing out the grade school history overview of the topic.
As for whether the threat of invasion is the deciding factor on the official ROC policy.. I think it's better explained by the fact that everything is going fine with two Chinas. They trade a ton, everyone's happy.
Why mess with that just because the diplomatic positions don't make logical sense?
What part of China has threatened to invade them over changing their policy makes that policy a coerced statement and not an accurate representation of their intent do you not understand?
You really think China's 5 seconds away from a bloody invasion? China is Taiwan's largest trading partner.
Everyone's getting rich, in both countries.
Taiwan is and will remain independent, everyone knows this, China doesn't care.
50% of people in Taiwan believe that China will invade if they declare independence.
So yes half of the country thinks it's a credible threat. [1, 2]
And only 6% think their situation has improved over this time last year. So "everyone's getting richer" certain isn't the perception in Taiwan.
1. Survey http://www.taiwansecurity.org/app/news.php?Sn=15761
I'm not taking a side on PRC vs ROC, maybe you're misunderstanding me. I just honestly thought it was taken for granted that that's pretty unlikely. All the talk about who's sovereign has been polite fiction for some time now.
(and, I'll admit I haven't done a ton of research on Taiwanese public opinion, but unless/until I do so, I'm going to take 'taiwansecurity.org' in English's takes with a grain of salt - Ahmed Chalabi sounded good too)
The survey was done by a Taiwanese University in cooperation with Duke University. If you want to dismiss it without doing any research then have at it.
This seems like even more coercion opportunity on the part of China onto Taiwan, tbh. I doubt Taiwan has similar leverage over China to asswert its independence.