I am reasonably familiar with it, you're missing mentioning why the US defended Taiwan initially. The US stopped any formal defense of Taiwan in 1980, not to the 1990s. During the period it did have a defense treaty it was within the context of creating an anti communist bulwark, and such defence treaties (even with highly suspect partners) was the bread and butter of geopolitics in the Cold War. It was not because of some deep love of Taiwan or democracy, in fact Taiwan would only become a democracy after the defense treaty was terminated. And "ardent supporter" is a very tricky term, the US signed a declaration for the One China policy, which is completely against the idea of Taiwan as a separate nation(although at the time the KMT and people largely did not view Taiwan as an separate nation).
The silicon shield is undoubtedly a significant part of the calculus around Taiwan, especially wrt direct military intervention. Successive administrations have clearly shown their emphasis on maintaining access to key strategic resources (the Middle East and oil).