ATF/F-22 was a monumental undertaking, both in terms of its technical scope and its financial commitment. The teaming was purely done for the latter reason. Early on, there were some true technical synergies from the teaming, and Sherm Mullin's insistence on co-locating the team in Burbank was a key enabler:
- Lockheed Burbank's deep knowledge of very low observables (F117, Quartz, etc), along with integrating very complex avionics suites (Quartz, P-3, S-3, etc -- for the latter two, read Sherm Mullins' Mitchell paper and his oral history). Lockheed Corp. leadership's skill overseeing the development of very sophisticated strategic systems (Trident, space ISR, etc).
- GD-Fort Worth's top-notch advanced design capability (pre-"digital engineering"), which proved invaluable in terms of conceptualizing and integrating weapons, subsystems, etc.
- Boeing-Seattle's "deep pockets" as well as its experience in complex avionics integration and large-scale structures. And last but certainly not least, Boeing-Seattle was in the good graces of AF leadership, because of what many in Dayton and Washington DC believed, correctly or not -- Boeing along with Vought bailed out Northrop on the B-2 development program.
Upon award of the EMD contract, this teaming arrangement required the immature preliminary design to be sliced into thirds. Not to mention the size of the workforce grew by an order of magnitude. From 1991's start of full-scale design to 1997's start of flight testing, it was very much like 3 companies were off doing their own thing, with a come-to-Jesus meeting every once in a while. There was essentially no "co-location", except in certain crisis situations.
To briefly address the California-Georgia swap question, I think it contributed to the inefficiencies and longer cycle times to accomplish key milestones, primarily due to the culture differences between the California and Georgia companies. Actually the learning curve of Georgia management was a bigger problem than the learning curve of Georgia engineers and shop personnel. But afterall, it's not like Burbank knew better how to design and build the Air Force's front line fighter in a 3-way arrangement of proud (read arrogant and egotistical) companies.