The GPU hardware rots and becomes obsolete in a matter of years, but the national infrastructure required to support the physical sites isn't going away. Things such as...
- improved power distribution networks
- logistics arrangements to build and support the DC sites
- lots and lots of new fibre interconnects to support the massive bandwidth needs
- hopefully: better power delivery planning laws
- plumbing infrastructure, because all that hardware requires cooling
Some of the DC sites will be decommissioned from their initial use, but given the physical security requirements, might morph into handy higher-security industrial facilities with only small repurposing. Such reuse cases would especially benefit from improved logistics (see above).