It will still be building that knowledge inside Europe. Rocketry in general is deemed to be strategic so it's OK for any country to invest money in that, keep scientists and engineers on the subject, keep the industries alive, etc. It's not only about access to space, it's also about defense.
> will still be building that knowledge inside Europe
Ariane 6 cannibalises Europe’s chance at being more than an also-ran in space:
“An Arianespace manager pushing his company as the only solution to Europe’s launch challenges isn’t that noteworthy. However, the fact [Arianespace’s CEO] urges the need for a ‘reusable heavy launcher’ is notable, considering his previous noncommittal remarks about rocket reusability. The certainty of his statement leaves no ambiguity–Ariane 6 just won’t be able to compete in the global market. It will take a (single and expensive) reusable heavy launcher (manufactured by Arianespace) and (funded by) a unified Europe to compete (with SpaceX).
While [Arianespace’s CEO’s] admission of reusability’s future in Europe is surprising, his constancy in his attempts to keep European space activities hostage to Arianespace is not. To be clear, he wants European taxpayers to fund reusability development and manufacturing only through Arianespace. He believes Europe can’t afford more than one reusable heavy launcher and that if Europe were to pay for a reusable rocket, then Arianespace must manufacture it.”
You're under the misconception that it makes sense for Europe to have a launch vehicle at all. The launches happen in French Guiana. The only reason why you would build it on the European mainland is as a jobs program for Europeans.
No commercial entity would come up with the idea of building a launch vehicle in Europe. Making a rocket reusable means that it would not leave French Guiana far behind. There would be less need for rockets from the European mainland.
> under the misconception that it makes sense for Europe to have a launch vehicle at all. The launches happen in French Guiana
Launch controlled by Europe. French Guiana is Europe, geopolitically speaking. SpaceX building rockets in Europe wouldn't give Brussels the strategic autonomy of an Ariane launched from below the equator.
