I think that modeling military is the easiest thing we can do. It is what most board games do, after all, albeit with varying levels of success/realism/fun. Even just listing "126 Infantry Divisions, 22 Panzer Divisions" etc... is sufficient for most purposes. If you want to go in depth, it's honestly somewhat trivial to keep detailed records of each nation's armed forces down to the division level. If you don't want to write that much, move up to corps. The reason it's easy is because adding more infantry does not increase the complexity of the system.
I think the real reason modern NESes don't exist, aside from the popular perception that modern times just aren't as "interesting" as past times (specifically people who think nukes have somehow ruined the "fun" of warfare), is because modeling economics is such a major pain in the ass. I know it's a conversation I had with EQ a lot, and more recently with Masada, that while for pre-20th century IC or EP works reasonably well as an aggregate spending capabilities stat, the more realistic you want to go, the more you have to account for, and failing to do so obliterates verisimilitude. Furthermore, even in a 19th century situation, how do you realistically differentiate between industrial powers, merchant economies, and vast volume economies (say the UK, Netherlands, and Qing China respectively)? Simply using IC is not satisfactory at representing the ability of a country to produce, much less the ability of a government to... govern.
That having been said, it still works OK and in fact I think IC is the best we can do because you can add more non-IC IC stats - like in SysNES2, there was also a science stat, a talented workforce stat, etc. which were all hard integers, and I think it worked well from a playing perspective but it was obviously not very realistic - but the more modern you go, the less you can get away with. There's no excuse not to try to model GDP and trade balance and in fact you kind of have to because the notion of IC simply fails to encapsulate enough phenomena when you apply it to a modern, globalized economy.
And then the real killer is... okay, we can model stuff produced, we can model different productive sectors of an economy, and with enough creativity and BS we can model supply and demand, but... the more you add to the system, the more complex it gets. Two interacting economies behave very differently from an economy in a "vacuum," especially when governments start changing the rules and doing their own stuff. Bozhe moy, it's too much, I say! And now you want 200 interacting economies in the modern day? Sheezus.
Source: Listening to Masada-sama's lectures on economics and trying to incorporate it into a NES and failing very badly.
You damnable elitists and your fancy, pish-posh "chats".
