The problem with Taiwan is that they invested heavily in Communist China when they built their high-tech factories there. It's as simple as that. The head of major high-tech Taiwanese companies, like Foxconn (whose Founder and head is reputed to be a close friend of Donald Trump) also, have, unknown to most, publically backed reunification with Communist China! By choosing to put their factories in Communist China, Taiwan did more than just shoot themselves in the foot, they may have created their own downfall.
America supports Taiwan since it always supports Freedom and Inalienable Rights and Liberty over Dictatorial Control, Censorship and State manipulation of Citizens that is the trademark of Communism. Taiwan should stop doing business with China, and put its manufacturing plants and factories in the USA if it expects the USA to defend it in any potential war with Communist China.