Given the cadence of China’s military development, the failure to successfully onramp to the next generation of weapons technology, despite the massive lead time the US started with, is not an encouraging sign. In a lot of fields China is already reaching parity or preparing to leapfrog. I wouldn’t interpret stillborn programs as taking the time and money to look outside established concepts. Anyways. We should move this discussion elsewhere if we want to continue.Most of these programs were about taking the US another generation ahead from already being in a position of technological leadership. From this perspective, it's understandable they took more time and money than following established concepts and making smaller improvements would have.
Additionally, for the F-35 the price has been kept under 90 million dollars per plane, which is very reasonable considering the capability.