Escalation with China, which is not what the US currently wants, hence why they keep military support in check but nothing more. However it is the USA, so they likely have a ton of direct influence in Taiwan’s government, so it could be just as well considered a vassal or “shill” state, or at the very least decently under control.

Currently though, they are cutting off China from Taiwan’s chip supply which is forcing China to kick start their lithography fabs at home, and is also the reason why a ton if the RISC-V software is coming out of Chinese universities (open ISA unlike ARM and Intel x86).

The USA likes to keep a resemblance of global leader, so they’ll never actually annex any country even with popular support, just control it with the easiest method available, which is usually just espionage and a crap ton of bribes.

It would only happen in a military conflict, which is also unlikely despite China trying to hype up their military all the time. They don’t currently have the resources to take on Taiwan even alone (in a prolonged fight) just due to the sheer logistics of transporting a ton of troops onto the rather heavily defended Island.

They want the fabs, but they can also just as easily play the long game and eventually make them at home in probably less thana decade.

Also not to mention Taiwan probably has actual social care and proper facilities for its citizens, so I don’t think anyone would want to join exploit heavy USA.