Most of the previous 'failed projects' were because of other reasons rather than technical, as stated the Northern Ireland ones suffered due to the peace process, the USN navy, again funding cuts.
The whole argument about not going into the warzone was touted by lots of people who didn't understand what was so great about the cargo capacity of the KC-30. That's what those shiny C-17's are for right?
If you took a timeline of the flying wing, I'm sure it would look identical, a couple of successes in there, with plenty of projects that never made it past the drawing board due to financial reasons ( or most likely, people don't like the idea because it's not two wings fixed to a tube).
Needless the say the flying wing has some HUGE advantages over 'conventional' pointy aircraft.