Besides loath sentiments against China which have formed collectively by the relics of half-breed Jap, the rancor out of land-reform "victims", Chiang's overwhelming anti-communist inculcation, and recent anti-China education, I think the most plausible explanation that makes islanders feel extremely reluctant in seeking unification with China's Mainland is their long-time recognition that Mainlanders are poorer "relatives".  You know, snobbery is always one of human's natural weaknesses.

Now Taiwan's GDP is only 5% or less in whole China's, being just a province ranked in upper tier.  Although GDP per capita of China's Mainland is still nearly half as much, the metropolitans of similar population like Beijing, Shanghai, Guangzhou, and Shenzhen all emulate to that of Taiwan's.  The gap of average living standard between both sides of the strait is swiftly narrowing, that's why you can hear some stupid islanders, acting like ostriches, utter inanities that Mainlanders yet to afford tea-marinated eggs or instant noodles. 

But there are wiser ostriches in Taiwan.  What they can do to protect their brittle, injury-prone hearts when they are facing the reality?  Simple.  All they need is to state that those wealthy, developed countries are almost all democratic nations, so democracy is an universal value that fits all.  It seems a long way before China can be as rich as those "wealthy" countries now are (Probably that day will never come unless new energy and some revolutionary innovation are found.  How can this globe afford a populous China, as well as the runner-up India, to live by like Americans have long been doing?); therefore, according to their logic China's democracy will be a faraway target, and China has to wait, so does Taiwan. 

No wonder the islanders, especially those Dutai advocates, refuse to unification by demanding democracy from China's Mainland like chanting litanies every day.  (Have you noticed that Taidu advocates don't call for democracy from China any longer, for the term is just an euphemism for independence, and now they think they've achieved their goal already.) 

P.S.  Please also see "吴靖：帝吧“野蛮人”都知道主动沟通，文明人只知道发射话语导弹？" at http://www/guancha.cn/wujing/2016_01_24_349047.shtml