This issue comes up from time to time and I'll write again what I think and the solutions for fixing it.
Firstly, let me say that it does come at some considerable economic cost to achieve these results in the first place. The OP is wrong in that and only that.
Okay - so 30*10*1000 = 300,000 supplies and to maintain the engine bonus the same again in engine expansion and repair. The engine bonus uses engines and as soon as the stockpile drops below 500 engines, it is lost. This is without considering the much lesser cost of HI, supplies and manpower to expand them initially.
Next, there is the opportunity cost in not using these facilities to advance other planes.
R&D works on a 2/3's principle. 2/3 of the time till arrival will be spent repairing the facility, 1/3 in accruing points. So for factories a long way out, multiplying the factories is a good option for real returns on investment.
So, R&D is overpowered. Well, yes it is but there are a number of ways of making it less so.
- limiting number of factories dedicated to the same model R&D.
- Realistic R&D
- I've even seen a HR which talked about how much R&D max advance was allowed. Each year adding one month. So 42 = 2, 43 =3, 44 = 4 etc (Or whatever permutation you want)
- no Engine bonus R&D (hard to implement though)
2. Economic Mod.(I've done this with my game with Floyd)
- Add months to F & FB (as well as others) plane arrival date. . One month for each year (see above).
- no more than 1 upgrade to next model per model. So, A6M3 -> 3a but not A6M5.
- Advanced Engines moved months down.
- Changing engines for advanced models so they are not using typical engines.
- Engine costs increased for building. (later models only) Pity we can't do this for planes too! Or get to the economic multipliers for these things!
- Less R&D plants available.
- All R&D plants start at 0(0)
- Less non-R&D plants (so you need to allow R&D to become production)
- Overall making the player research even late '42 planes to get them on time.
-Reducing supply and HI production (while maintaining or increasing resource multiplier needs).
- Still testing a principle of prototyping (no arms) for my Options88 mod - which then can be used to further R&D on a real model / optioned models.
3. Code changes.
- R&D engine bonus eliminated. Not sure this is used a lot though as it is incredibly expensive to maintain.
- An overhaul of the 2/3 rule. Or something that changes the repair rate for later models.
- Reducing the optimum factory size to below 30. Or maybe better the other way. Increasing the size but halving the output.
- Economic multipliers for planes & engines exposed and while you're at it, the same for Arm / Veh etc.
- Making every plane have to go through R&D. Non-R&D = no plane (more R&D factories required).
- No R&D (but I love it - so would hate to eliminate it!)
AE - Supreme Commander Edition (Yes I am throwing things out there in the next bit ... )
- A move toward variability in plane stats.
- PTO II-esque R&D.
- HOI R&D.
- Design specs determined, producers sought, Ind delivered (In time and budget - yeah right!) - sort of what happens IRL. I really would love to make a game like this...
- No R&D.
- etc ...
Anyway, these are just some doodles as I prepare for another day at the salt-mines cause I rather talk about this than consider the pile of marking that is overflowing on my desk.
Night all ...