My reservations with the line of thinking that
@tphuang has expressed, is that I believe that the US will find it very easy to use political pressure to actively prevent the European nations to develop de-Americanized products to begin with, let alone sell them.
The real lever of power being applied which prevents nations from selling their wares, isn't that certain products have a certain percentage of US IP or US technology (that's just a formality), but rather those nation's geopolitical relationship (i.e.: geopolitical vulnerability) with the US.
The US can set the percentage of "US technology/IP" of XYZ product to
any level they want -- including to
0%, and they can still apply geopolitical power and pressure to nations to prevent them from selling specific products if they feel giving China access to said products would be detrimental to US geostrategic interests.
The US has shown it is willing to make extra-territorial laws for transactions that do not involve the US in any form, so this really would not be a big step forwards at all.
So, I think a more likely outcome for semiconductor and semiconductor-related equipment and technologies will be more akin to the ban on selling military equipment to China -- a wide spanning arms embargo that the US and its dependents all voluntarily ascribe to and where even the idea of selling such equipment to China results in condemnation and dog-piling onto the group which does so.
I could easily imagine the US making a law whereby they are able to impose sanctions/threaten geopolitical relationships with any nation (including/especially its allies) that has any companies under their jurisdiction that sell China semiconductor industry related equipment -- if anything, this is just one of the logical outcomes of the current US trend, and this isn't even the most extreme or severe potential outcome of the US trajectory.
The only thing which may prevent such outcomes, is if the industries in Europe and other nations like Japan actively lobby their own governments... But I think US pressure will be impossible to resist against, so that the governments in question will have to be forced to choose between their entire relationship with the US (and the US security/geopolitical structure overall) versus selling China domestic/de-Americanized semiconductor products, and I suspect they will not choose the latter.
In the long term, the only path forwards for China is to domesticate the entire, full tech stack, and/or to have parts of the tech stack with nations that are not geopolitically aligned with the US or geopolitically vulnerable from US pressure... but of course we all knew that.
That said, I'm sure there may be a time period in the future whereby some European companies can develop de-Americanized products and be able to sell China those products before the US makes laws and carries out pressure to stop them from selling de-Americanized products... but it's also possible that the US government seeks to go ahead of the curve and puts in legislation and applies pressure before European companies can even finish developing de-Americanized products, to pre-empt any equipment from reaching China at all.
