I'd say end of the Cold War made the USA second guess the need for interesting combat aircraft. The perceived reduced usefulness of such aircraft meant the development costs weren't deemed to be a useful use of funds (because the US government clearly has an "excellent" grasp on what is and is not a useful expenditure for R/D, or what is a useful combat aircraft for that matter).
I'd say end of the Cold War made the USA second guess the need for interesting combat aircraft. The perceived reduced usefulness of such aircraft meant the development costs weren't deemed to be a useful use of funds (because the US government clearly has an "excellent" grasp on what is and is not a useful expenditure for R/D, or what is a useful combat aircraft for that matter).
Would have likely been better then you know what..
And they didn't go into production because of the Voldemort of planes..
Lockheed saw more cash with the USAF's Arrogance on their snazzy new over priced design.