Remember in the 1950s when an airplane went from concept to flight in two years? I can remember. as a kid living on Air Force bases, seeing F-84s, F-86s, F-100s, F-102s, F104s and F-105s all at the same base over a 4 year period.
Now the DoD has to study the s#!t out of everything for decades then decide they didn't want it anyhow.
The Russians and Chinese take an existing design then continually modify it, new evolutions of fighters every couple of years.
The current DoD acquisition system is not designed to rapidly acquire high tech weapon systems.
It is designed to keep people employed in key congressional districts.