Have you read Boyd: The Fighter Pilot Who Changed the Art of War by Robert Coram? If you haven't, it's worth reading. It's been a while, and sometimes it's a little tedious, and Boyd does kinda go off the deep end, but his thoughts on weapons development and his fight with the rest of the Air Force was interesting. The cost and the lag time in developing new weapons systems exacerbates the problem in figuring out what weapons are needed, how they will be used, and what they will replace - and why. I have a feeling if Boyd were around watching the F-35 bandied as an A-10 replacement, his comment would be YGBSM! The military needs to learn the KISS principle or they're never going to keep enough of the new stuff up and running to have a chance of winning with it.