The development and testing process can be 5-10 years in some cases. My previous employer built and finished delivery of a batch of prototype microwave power modules before I started there. Six years after I came there the military (not sure which branch) gave approval for production and ... the engineers on the project had to find some way of replacing a key IC which had been obsoleted, had no equivalent, and had not been put into production by a semiconductor company that specialized in producing obsoleted components for military and industrial users.
Few companies are willing to put up with the high-risk, long-term dev/test cycles for military products that Congress can and sometimes does slash in half or wipe out of existence with a pen stroke.