If anything, the whole programme, from FCAS/Team Tempest/F-X to GCAP has lots of parallels to be drawn between it and ATF and EFA. Current phase of development would correspond to DEM/VAL, and just as Lockheed team and Northrop team had each their own FTB programmes, UK and Japan has their own as well.
Also just like DEM/VAL, there are two separate TD aircrafts, although Tempest CAD/FTD will fly soon whereas ATD-X/X-2 programme has already been concluded. Team Tempest CAD/FTD is taking longer than both the ACA programme, which took 3 years from contract award to BAe to maiden flight of EAP, and DEM/VAL, which was only 50 months long and took 4 years until first flight after contract award to Lockheed and Northrop. CAD/FTD will take 5 years.
In terms of programme management, EFA go ahead was given on 1985 and the two JVs for the aircraft (Eurofighter GmbH) and the engine (EuroJet Turbo GmbH) were established in 1986. GCAP is currently somewhere in between, as GIGO convention was ratified by the three partner nations' respective parliaments in 2024, but GIGO HQ and GCAP industrial JV are yet to be legally established. It is envisioned to be formed by the end of this year, so in terms of EFA, we're in 1986 phase.
A more comprehensive timelines for ATF, EFA and GCAP are as follows. I think it makes for an interesting comparison :
ATF
1981 - Programme initiation
1985 - DEM/VAL RFP
1986 - Lockheed and Northrop chosen, 50 month DEM/VAL
1990 - Maiden flight of YF-22/23
1991 - Contract award EMD
1997 - Roll out and maiden flight of tail number 91-4001
2005 - Introduction
EFA
1982 - Following ECA and ECF, ACA programme initiated between the UK, Germany and Italy
1983 - Contract for EAP to BAE as UK-only programme
1984 - EFA formed
1985 - Programme go ahead
1986 - EPA rolled out, maiden flight. Eurofighter GmbH and EuroJet Turbo GmbH established.
1992 - DA1 rolled out
1994 - DA1 maiden flight
2003 - Introduction
* should note that after German withdrawal from ACA, MBB separately pursued X-31 programme with Rockwell. X-31 programme was briefed to DoD in 1983, phase II (preliminary design) commenced in 1986 and had its maiden flight on 1990.
GCAP
before 2017 - Start of precursor programmes. ATD-X/X-2 flight test programme concluded, ground test and evaluation continued beyond flight test programme.
2017 - Initial steps of Anglo-Japanese cooperation
2019 - Plans for Team Tempest FTB, the Excalibur, revealed
2022 - Development of Tempest CAD/FTD announced. Merger of British and Japanese efforts into GCAP announced.
(from here envisioned timelines, timelines specified in the Japanese MoD document in red)
2025 - Start of system development activities, contract award to industrial JV
2027 - End of detailed design. Maiden flight of Tempest CAD/FTD.
2027/28 - Foreseeable start of GCAP international partnership according to Leonardo UK GCAP director, Andrew Howard.
2029 - Roll out of EMD aircraft
2030 - EMD aircraft maiden flight
2035/36 - Introduction
ATF took 14 years from EMD award to Lockheed until introduction, whereas EFA took 17. I should definitely note that the progress of both programmes were noticeably hampered by the end of the Cold War, as well as events closely connected to it. Obviously, EFA was much more severely affected due to troubles concerning Germany, hence a 17 year long development despite ATF being a much more ambitious programme aimed towards a more advanced design. In terms of programme goals, I think it's safe to say that GCAP is a far more ambitious programme than what EFA was in the 80s, though probably not as revolutionary as the ATF.
If that is a good enough indicator that GCAP could be developed in a shorter timeframe than the F-22, is not what I can tell. Though I could point out a few things; There has been an even greater shift to avionics, especially software than compared to before and after the ATF, and software engineering is very different compared to other disciplines of engineering. We have new ways of engineering, such as digital twin. We don't have the end of Cold War either, but rather we're witnessing a fresh start of CW 2.0. Japan is a much more reliable partner than what Germany was in the 90s.
Such points make me cautiously optimistic about the timely development of GCAP, although as I've said, I'm quite certain that 2035 deadlines would not be met. Even if the tri-national JV is formed tomorrow and contract awarded next week, they barely have 10 years until planned introduction, and in reality, they will have less than 10 years for development should the 2035 schedule be kept. I'd rather expect that the actual induction would be closer to late 2030s and hopefully before 2040 if things go alright. It might be a few years too late for the retirement of F-2, but I don't think it's going to be the end of the world. Plenty of air forces around the world operate their fighter jets well beyond their supposed end of service life.
Was a fun summary to make.