If you look at the world map, Taiwan is getting in the way if China wants to reach Japan or USA.
USA can use South Korea , Japan, Taiwan or pinoy land as base to shoot at China.
If china wants to shoot back at USA , those puppets will shoot it down.
So no choice, China must invade them if there's a war.
But it also means USA is just using them as a meat shield.
Taiwan should be difficult to convert to be part of prc since there should be American bases there.
Same for singapore, we have USA base at sembawang.
I personally think Taiwan going back to China will equalize power, China feels less threatened by all the surrounding American allies and USA will stir less.