Yeap, the important infrastructure is really the people. I imagine if the US saw something a kin to Russia’s mobilization to the border with Ukraine, there’d be a noticeable influx of Taiwanese immigrants coming to America.
Plus, I really can’t foresee an actual invasion across the Formosa that would leave much infrastructure intact. It’s basically an island fortress where your choices of combat terrains are urban or pacific forrest/jungle. Taking the island without leveling it first would be a prolonged blood bath.