I don't know why the military can't learn from a string of failed systems going back to at least the '80s.
1. Make Tough Requirements
2. Get Prototype
3. Prototype attracts some interest
4. Now the brass additionally wants capabilities X, Y, Z
5. Prototype now costs twice as much and is more failure
prone, and actually less mission-capable due to all the bolt-ons
6. Program costs goes up due to all the changes
7. We can't afford this!
8. Cut unit acquisitions by 50%
9. Wait? Our unit cost just nearly doubled because the real costs were all in design/R&D?
10. Now we REALLY can't afford this.
11. Cut orders by another 75%
12. So finally approximately 10% of the original order actually gets built, at a total program cost 2 or 3x what it was supposed to be, and a unit cost that's massively huge.
13. Program fails in the mid-to-long term due to maintenance costs and falling spares inventory.
HBO did a great made-for-TV movie on this called the "Pentagon Wars", which while fictionalized is only about 20% actually made up: https://www.youtube.com/watch?v=ir0FAa8P2MU