Too late for Dave, but that seems to be the way 6G is heading, or at least as a recommendation.
http://www.rand.org/content/dam/rand...AND_RB9759.pdf
Key findings:
• Joint aircraft programs have not historically saved overall life-cycle cost.
• The difficulty of reconciling diverse service requirements in a common design or design family is a major factor in historical joint aircraft cost outcomes.
• The JSF is exhibiting trends similar to prior joint aircraft programs.
• Historical analysis suggests that joint aircraft programs have coincided with contraction in the industrial base and thus a decline in potential future industry competition and increased strategic and operational risk.
• Unless the participating services have identical, stable requirements, DoD should avoid future joint fighter and other complex joint aircraft programs.
I would suggest a future where all three manufacturers, Northrop Grumman, Lockheed Martin and Boeing, all design, develop, build and sell different aircraft to be one where capability is maximised as well as reducing costs. There may well be some commonality in certain systems and structure technology (software/systems integration/engines/self-healing/stealth - for example), but each airframe optimised for role and basing requirements. I.E.: Naval F/A (twin engine - carrier optimised), and both heavy (twin engine) and light (single engine, extreme agility) land-based F/A aircraft. So yes, essentially G6 eqivalents of the -18, -15/-22, and -16/-35A.