Trade between Taiwan and China is something like $270 billion. Taiwan is one of China's biggest export partners (larger than Russia, Malaysia, France, Brazil) and one of China's biggest import partners (literally the biggest, I think).

Cultural penetration is significant and bilateral mobility across the strait is very high. Anyone who seriously sees hot war as a possibility is delusional. At worst, we may see a Kennedy-style quarantine of Taiwan if too many US weapons make their way to the island.