The F-XX and F/A-XX aren't even close to flying their demonstrators yet. They're testing systems, but they're nowhere close to flying. The Pentagon
hasn't settled on the requirements yet.
Ah. Artist's impressions are a fools game. It's a fantasy until it actually starts getting prototyped, build and delivered. Russia seems to
generate quite a few artist's impressions of things that would never get built.
For instance, this is an artist's impression of my new house...