They later built two prototypes to test for the Navy, decided a common airframe wasn't going to work, and built the F14 using the lessons learned from that development effort instead.
The three variant JSFs are essentially three separate aircraft run by one program office.
The USAF and USN used a common aircraft in Vietnam to great effect -- the F4.
The JSF per aircraft cost is going to be less than the F18 by the time the program is finished.
They're actually shutting down the joint program office because it is now in fact, three separate aircraft. Which again, puts lie to the whole rationale of the program in the first place.
> The USAF and USN used a common aircraft in Vietnam to great effect -- the F4.
The F4 did decently, and if we use it as a guide, the Air Force and Navy variants should have been their own program, and the USMC should've had a separate airframe to accommodate their STOVL requirement. But that's not what we got, and that STOVL requirement is a large reason the platform has some big fundamental compromises.
> The JSF per aircraft cost is going to be less than the F18 by the time the program is finished.
People keep promising that, but the DoD and Lockheed keep laying games with how they quote costs in order to make it seem like cost parity is closer than it really is. Flyaway costs for the F-35 keep getting quoted against procurement costs for 4.5 gen aircraft to make the F-35 look better than it is on cost.
The USMC used the F4 alongside the USN as they always have. USMC aviators are trained as Naval aviators, deploy with USN ships, and support USN missions as part of the CVW. The ARG concept is different, and USMC STOVL fixed wing wasn't a thing in Vietnam. It's a more modern concept. You're projecting things that didn't exist into the past.
There are no compromises between the platforms for STOVL -- the JSF-B is a separate aircraft as it has been since the beginning and as you say in the sentence above. JSF-A and JSF-C are different airframes with different requirements and different capabilities.
So while the different variants have different wing surfaces there is no denying that the Air Force and Navy versions would've been designed differently if the airframe didn't have to fit a lift fan in it.
So then you're back to the fundamental question of why even bother. Parts commonality is 1/4th of what it was supposed to be. Costs are nowhere near what they were originally billed as, even with the most optimistic estimates.
Really the only virtue of the JSF approach was that it made the program too big to fail.
The size of the aircraft is driven by the need to carry large amounts of internal fuel and all internal stores, not the need for a lift fan for the B model. This allows all three models to operate with a reduced cross section for an expanded set of missions, which is the purpose of the aircraft.
Parts commonality is essentially non existent except for the engine and parts of the avionics -- that does make a difference and is a cost savings, but it's not the issue you make it out to be.
Costs are better than they were sold as, and their availability rates are better than they were sold as, and their accident rate is so low as to be non existent. It's a phenomenal aircraft and a capability that's going to completely change the balance of power in some regions of the world.