If a war between China and US happened. A war situation will trigger. Iphone will cease shipping from China. Apple stock will nose dived. Wall street will tumble. This is the thing nobody wants to see...There are three scenarios for the Taiwan war:
Scenario 1: US does not interfere, China wins.
Scenario 2: The US and its allies intervene but China wins, the US and its allies withdraw.
Scenario 3: US and allies intervene, China fails. In this case, nuclear weapons are the only solution. China will use nuclear weapons to attack all countries that directly or indirectly interfere in the Taiwan issue. The result of a nuclear war is that all countries directly and indirectly involved in this war will be destroyed. If China loses, everyone loses. That is why China needs to build as many nuclear warheads as possible.
If Taiwan is being invaded. The world just watch. Everything goes normal. Wall Street will be saved too. Life goes on as normal.