There are countless industries with complicated global supply chains sensitive to violence or other political aggression. Having to repatriate all manufacturing to the USA is one alternative to a global military force, but that is probably more costly than 750 billion a year. TSMC is just one example of a crucially important industry ostensibly supported by the US military.
I agree there is room to cut the military budget. My argument is more that the US military serves a valuable purpose beyond the college sophomore 'imperialism is bad' arguments that many in this thread like to make.
This is the crux of the issue. The company I retired from invested heavily in China for component manufacturing. It started as just "hardware store" type parts but soon progressed to more complex parts and eventually critical parts. All because it was so much cheaper. Then about 10 years ago they realised they were loosing the knowledge to make these parts at home and so started a strategic withdrawal of complex and critical parts from China. China still makes the majority of the parts but there is the capability to quickly ramp up production at home should everything go to pieces.
In a previous post just above this I mentioned that I would guess the current US policy is to have enough in house capacity to meet defense and other critical needs but for consumer needs they are happy to go with the lower price source and rely on their not being any invasion. Hopefully they have plans in place to ramp up production should everything go to pieces in Taiwan.
One final comment: To me the bigger issue is not "Who makes the chips?" but "Who makes the machines that make the chips?" If these machines are all made in Taiwan then the West has seriously put itself behind the 8-ball.