They don't and they haven't since the 80s. The military needs reliability in harsh conditions above all else and modern processes can't deliver that. The military also doesn't care about the economic benefits of die shrinks so that driver is missing.
Front-line needs reliability, but the military has a lot of backend too, and they may well be interested in a secure supply of powerful GPUs running all kinds of AI-type workloads that don’t need to be on the battlefield. Something like continuous satellite surveillance of enemy territory with automated flagging of suspicious activity.
