Because this is a game between China and America. What the people living in Taiwan wants and chose are frankly irrelevant and entirely ignorable at this point.
Even if a pro-reunification candidate wins with a 99% majority, the CIA will just assassinate him/her and stage a coup or similar other crisis to justify direct military intervention to stop peaceful reunification.
Ma Ying-Jeou was closest to pro-unification candidate in decades. He is still alive.
They just did the stupid sunflower revolution on the FTA that was negotiated.
Very stupid because now all the major Taiwanese companies are losing ground to mainland companies.
Maybe it was inevitable, but there is an undeniable exodus of Taiwan scientists and engineers to the mainland, enough that the DPP government outlawed it. They talk about semiconductors, but really this is affecting all industries, even basic ones.
On the high side, there are an estimated 2 million Taiwanese working and living in mainland. That is almost 10% of the population, an insane number really.
Is Taiwan really more attractive than Mainland, Singapore, HK, or even South Korea for any kind of skilled worker? The only people Taiwan is attracting nowadays are white LBH, I guess they are okay for the crappy English teachers industry...
CIA is not an invincible force of influence. They have to face the economic reality.