[walrus01]

Making the airframe even more rigid and capable of resisting extreme forces also makes the wings and fuselage and control surfaces much more heavy, so you end up in diminishing returns. Look at the 'final' revisions of the F16 sold for export that have had all sorts of pylons and conformal fuel tanks stuck onto them, compared to the original prototype. And that's just making it more heavy and laden down with stuff, not more capable of extreme maneuvers.