I worked on the Boeing-Sikorsky Comanche helicopter. That aircraft was also intended to be a multi-role aircraft, intended to provide stealthy armed reconnaissance and attack roles. The project was canceled after investing approximately $7 billion.

Multi-role aircraft are intended to save money, and it sounds like a good idea. You save money training pilots and ground crew. You save money with parts, support equipment and logistics. Unfortunately, the multi-role aircraft don't do the individual roles as well as aircraft designed specifically for the individual roles. I have yet to be convinced that the F-35 will be able to do close air support as well as the A-10.

When you put together the Marine Corps, the Navy and the Air Force requirements, it's really hard to come up with a multi-role aircraft that does each role well.