Because individual EU states now have no choice. The alternative is to accept being a contested beach ball squeezed between the US and China, and with other regional powers taking advantage.

The EU had already lost the initial race in HPC and AI by 2011-16 when EU institutions and state-level institutions failed to support the kind of public-private collaboration that was happening contemporarily in the US and China. I remember noticing on visits how EU nationals were often working on or closely with the Guangzhou Supercomputing Center in large part because capital that could monetize fundamental research dried up due to the Eurozone crisis.

Similarly in Quantum, barely 15 years ago, a large portion of China's current leading quantum researchers like Pan Jianwei were still working closely with European researchers like Anton Zellinger at institutions like Wien, Geneva, INRIA, and the Max Planck Institutes to close knowledge gaps that remained. While the gap has now been reversed, it can be managed because having some sovereign capabilities at least helps reduce the risk of being at the mercy of export controls.

Basically, the EU and individual EU states have one last chance to recapture the frontier lest it's gone.