Have you noticed that countries that actually need to defend themselves against genuine credible military threats manage to do a lot better? (Israel, Russia, China, Iran...)
The real reason that most Western defence procurement is so immensely inefficient from a military point of view is that it isn't really a military exercise. Its real purpose is to transfer money from the taxpayer to the "defence contractor" (armaments manufacturer) as rapidly as possible. As long as the product looks vaguely military, that's good enough. After all, it will never be used in anger, and it isn't meant to be.