I think you're reasoning about it from the wrong end. The implied precursor I took from the article was that another nation suddenly decides to remove access t

I think you're reasoning about it from the wrong end. The implied precursor I took from the article was that another nation suddenly decides to remove access to a critical technology, via coercing or ordering the company supplying that technology. "Technological sovereignty," in the context of the article and quotes, would mean a country has the means to continue without that access. This doesn't mean creating a commercially-viable, world-leading industry (there can only be so many of those!), but does mean having a plan and emergency suppliers who can make functional substitutes. As an example, the US's strategic petroleum reserve made it sovereign in the matter of energy (effectively, and pre-recent production increases). Which is also a good example because it didn't mean 1:1 replacement of 100% of supply volume, but rather replacing enough so that alternate suppliers can be switched to and restricting access lost its power. But that was my read. Ymmv.