My thoughts on this are always related to "skin in the game": does it matter personally to the people making and procuring the systems, especially at senior management level, whether it actually works?
Back in WW2 it definitely did, especially in the UK where bombing had no respect for the class system. Winning or losing the war would make a personal difference.
But since then? All the wars have been overseas with no real threat to the mainland US; there was a real technological race against the Soviet Union, but that ended in the 1990s. The post-911 wars were more of an excuse to settle scores and play the Great Game than a real effort against terrorism (no pursuit of the Saudis for example).
The consequence is that the main thing that matters is selling the technology to the Pentagon, or promoting a career inside it. Nobody really believes that if they procure a crappy IT system the enemy is going to fly a 747 into their office. Someone might get killed, but nobody they know or who matters, and it's never going to come back to the project manager or procurement person who made terrible, expensive, uninformed choices about technology.