Cancellation isn't failure. By that point it was clear that non-stealth high altitude bombers were going to be completely useless within the next few years due to advances in missile technology.

Actually, no it wasn't. What was clear was that low altitude bombers were going to become useless due to look-down shoot-down radars. High altitude and high speed bombers were and are the best non-stealth alternative.

>High altitude and high speed bombers were and are the best non-stealth alternative.

Which are carried by interceptor aircraft - meanwhile the long-term shift was clearly towards anti-aircraft missiles., and stealth was only a few years away. At this point the F/A-117 was already pretty far along in development.