They literally have factories with employees of various nationalities producing those goods in china right now.
Only the USA citizens working in those chinese factories quit.
It is utterly delusional to think only USA citizens can have expertise and that all other people were just there to make coffee and give blowjobs to the glorious USA citizens who did all the thinky work.
You are acting like there's more in common than there actually is, and over-simplifying on top of that.
How many countries in the world design cutting-edge microchips?
How many countries in the world build cutting-edge microchips?
How many countries in the world make the
tooling that microchip foundries run on?
The list answers to each of those is very short, and the only place that does
all three was the US, until Intel's attempt to produce the latest generation of smaller dies failed, though I've heard they're catching up. Nobody else even approaches doing all three.
China has spent billions of dollars and a decade+ trying to match western, Taiwanese, and South Korean chip fabrication standards.
They've
failed.
They have to import talent, designs, and tooling, to produce stuff that fills out the middle end of the market, without that all they have left is the crappy chips that go into your smart TV, smart coffee machine, etc, etc. They may not even be able to keep that up without all that imported talent.
Up through the 90's and into the 2000's, AMD and Intel both produced in the USA. That started moving overseas, but it's already in the process of starting to move back, and the designs and tooling are still developed in the USA.
China doesn't
have a stable of European firms and talent that can replace what the US has withdrawn. If they scrape and reach, they can probably replace a small fraction of mid-grade production with European support, but Intel and AMD are both American companies, and the producers of secondary and supporting chips and chipsets tend to be American or Japanese/Korean/Taiwanese.
There are some European firms, unlike the industrial revolution, the digital age took off in America, and has been an American game since day one. There's a reason that there's no European firm offering to build the EU's 5G infrastructure. There's a reason that while 2-3G cell phones were produced by companies all over the world, smartphones narrowed down to a handful of manufacturers, Samsung, Apple, Huawei, and maybe one or two others having a meaningful percentage of the market.
The cutting edge of microchips is just about the most brutal business to be in. Each iterative generation of design costs billions to research and develop, and if a design fails, you have to either sink that much money into a new one, or go out of business altogether.
As soon as you finish one generation of development, you need to both keep a team dedicated to refining that chip/chipset,
and launch the next R&D cycle, because you can damn well bet that the competition is too.
Ever computer, every car, ever smartphone, every piece of advanced industrial machinery, every piece of advanced military hardware, all of these industries are incredibly hungry for either the absolute cutting edge, the reliable and ruggedized version of last generation's tech, or both at the same time for different applications.
TL;DR: This is not an industry that you can just hire someone else to do the job. There's 2-4 sources of competent talent who are on top of the game, and those are all in the US, Taiwan, and Korea. The runners up are in those nations plus Japan. If anyone else has that level of capability, I've not heard of it, and when the US pulls out of China, you can bet your ass none of those other three are going to take a shot at it.
Your alternatives from Europe are going at least two generations of technology back, and by the time you've managed to copy off of them, you'll be
another generation back.