Errrm - the N-156 was conceived from the outset as a low-cost fighter. The trainer just got sold first.
Where do these young fellows learn history?
The V-22's an interesting case. Yes, it "works" and it does some unique things that helos can't - and so it should, when you compare both its cost and payload to a CH-47.
However, over the period where the merchants of transformational, revolutionary change directed a bazillion dollars into V-22 and Comanche, the Europeans built two major companies around good conventional helicopters and booted the U.S. out of much of the global market.