Hmm, I'll remember not to PWD in future, that was a bit too smart assed in tone. What got me to reply at all is two things.
1. In the past two or three years, I keep seeing the -56 brought up by advocates of (fill in the blank). This was what got the "must post reflex" going ...
2.
the machines they attached it to were sunk by political and inter-service infighting.
If you've been in the business 45 years, then you know as well as I do the following:
... but as with all programs the devil is in the details, and there are competing programs, and even with Uncle Sam only so much money for the rotary wing bubbas. The people buying helicopters in the late 70's early 80's, and specifically helicopters in the niche AH-56 was aiming for, were fitting together the Big 5 weapons systems that were the back bone of the Fulda Gap mind set (Blackhawk, Abrams Tank, Apache, Bradley, Patriot). And they needed to be bought in significant numbers. Political infighting? I'll offer you a different reason. COST and TIME. For full rate production you don't buy tech because "it's cool" (Oh, wait, the USAF do that all the time, sorry
). You buy it to fit a core mission requirement.
When you make something too expensive to buy and maintain in the numbers required, you don't get the order.
The reason I offered Comanche as a second example is directly linked to the above. A fine helicopter, a fine weapons system, FBW, Low Observable, some new applications of materials, a step forward in a variety of ways for the industry (Boeing and Sikorsky and others) that while it had been under threat over the money during the Clinton austerity regime eventually ran smack into TIME and MONEY as major acquisition obstacles. (IMO, Army and DoD were short sighted in that, but I am
massively biased and not a neutral observer at all, not to mention I felt the Army over wrote the requirement and were unwilling to go single pilot, which would have made a significant difference ... but that's all water under the bridge)
Again, apologies to you for the tone, that was bad form.
I find the "why" that you asserted to be both unsatisfying and inaccurate.