growing economies could finance more infrastructure

countries are going to need geographically distributed nuclear fission energy 

and/or geographically distributed covert fusion energy 

and/or immense amounts of renewable energy  

and/or geographically distributed massive battery storages 

to power energy weapons that destroy swarms of: 

nuclear missiles, missiles, hypersonic projectiles, projectiles, hypersonic missiles, hypersonic drones, drones, hypersonic military aircraft, military aircraft that swarm the atmosphere all at the same time 

to overload defense systems