While it may be true that cost advantages are in that specific quartz, it is not some irreplaceable product. It absolutely would be possible to use other quartz, which would require more processing and increase costs.

Do you have any actual examples of things which could not be in sourced into Europe? I am very aware that for many reasons, among them costs, semiconductor fabrication is spread globally. But is there an actual reason why it would be impossible to have every single one of these pieces in some capacity in Europe?

Europe is continually moving further apart politically from both the US and China. Relying on the US for supplies and betting on Chinese, Taiwanese peace seems increasingly foolish. How can Europe secure itself in such an environment, without its own semiconductor supply chain?

A better example is the EUV lithography light sources used by ASML. They are manufactured in the US by a US company ASML acquired with technology licensed from US government labs. That critical part of the business is American in all but name.

It is possible that the EU could develop their own state-of-the-art lithography light sources but for now ASML is dependent on the US for it.

Silicon for solar cell production is currently being mined and refined in Sweden. What would it take to adapt that production line for semiconductor-grade silicon, I wonder.