I do not know the real answer, but my guess is this manufacturing was offshored like everything else because almost anywhere outside the US is cheaper. Mexicans, Indians, and almost any other impoverished people were too stupid to manufacture semiconductors. The Chinese are smart enough but their “don’t give a shit, push units out faster” attitude made them incapable of making semiconductors that worked (they can put chips on circuit boards though, still better than most).

That only left Taiwan. Poor enough to be cheaper than the US. People smart enough to handle the job (mix of Chinese and Japanese). Not horribly corrupt and confused by the concept of quality like the Chinese.

The first question is obvious. To answer the 2nd question you have to realize that America is currently the dying Ox, and today Netanyahu likely talks about China in the

Semiconductor manufacturing is very very competitive. The cost of mfg each chip can be cut by increasing wafer size and/or reduced geometries. There are manufacturing limits to these variables. The equipment required to use the biggest silicon wafers and create chips of the smallest geometries are outrageously expensive. Even the buildings containing these fabs must be vibration proof.

In the ealy days grants/contracts from Mil/Aero had helped many young US semiconductor companies to grow quickly.

America has had a few older semiconductor companies, a great consolidation of these companies took place in the 1990s through buyouts - stock prices were soaring as US jobs went off shore ; product obsolescence, efficiency and innovation determined the winners and losers 1980s-2001. During Bill Clinton's first term the tide shifted in another way. Military/Aerospace chip manufacturing no longer had to be manufactured stateside. Then we had another thinning of the herd with the dot com crash.

TSMC has been leading edge semiconductor manufacturing for at least 30 years. Their process technology is top shelf.

This high quality FAB opened the door for American semiconductor manufacturers to remove the costly fabrication process - expensive American fabs, employees, etc and simply contract the wafers to be reliably made by TSMC on their stable processes. US companies could avoid expanding their own fab capacity by using TSMC as a buffer if they designed to TSMCs process.

The surviving fabs in the US have upgraded their equipment too, but for many the chips they make may contain more analog circuitry which won't benefit much from smaller geometries. They are still competive cost wise on smaller wafers so these US fabs continue. Then there are the cutting edge US fabs by the most successful like INTEL, but they make their own chips there and are sized to support an anticipated demand for their product. I'm not aware of any US fab with TSMCs business model - you design it to our process and we will make them for you. It would require billions per fab to recreate.

2nd question. My opinion is as long as we have access to the same bleeding edge equipment vendors, we can recreate the capacity here in 3-4 years - but that equipment likely has TSMC chips in it too. China would certainly have a time advantage and meanwhile American companies depending upon TSMC for their chips will be blackmailed by China to share their IP. China can control products that currently use TSMC chips - computers, phones, tvs, cars ...

My 2 cents.