Also, the supply chains do exist. Shi + Brotherhood of Steel + NCR + Vault City.
It's sort of silly to debate realism here, but my point was that
all of the modern world is incredibly fragile. If humanity were wiped out, houses built in 1800 would more likely be standing in 2050 than house built in 2021. By 2050, ancient Roman highways would be in better condition than American highways. And even worse than structures and infrastructure is technology. The operation of our technology is incredibly dependent on things like reliable electricity at a certain current. And the
maintenance of our technology depends on incredibly robust supply chains for (1) replacement parts when they break down; (2) replacement devices when the whole device breaks down; (3) specialists capable of replacing those parts and devices.
Even with essentially infinite money, infinite supplies, and infinite supply of experts, our technology fails due to maintenance problems and wear-and-tear.
So when I say there aren't supply chains in the FO universe, I don't mean, "There is no way to transport any good any distance." Obviously there are caravans and there is trade. But what I mean is, it would be completely impossible to scavenge the parts and or even the materials to make the parts (including things like, say, rare earth metals). Even basic things like copper wiring would run out and be irreplaceable. The broken supply chains are that incredibly complex web that is necessary to keep the flimsy modern world from just falling apart. Scavenger caravans aren't going to cut it.
The reason the post-Conquest American example is at least a little instructive is that it shows that the apocalypse in FO wouldn't be a sharp drop followed by an upward recovery -- it would be a sharp drop followed by a downward slope with additional sharp drops as it went. It's not plausible that you would be seeing
more advanced technology less than two centuries after almost everybody died, almost all infrastructure was destroyed, the ecosystems were destroyed, and there was worldwide political collapse. We're not talking Europe post-WWII where there was at most a 10% population drop, where the land was still very fertile, a great deal of infrastructure was still intact, the basic social structure was intact, and there was massive outside capital to flow in. So even if we stipulate that Reno "didn't get nuked or suffer from fallout," it would collapse as lack of food, water, electricity, and political structure caused a complete social breakdown.
Shifting from realism to theme -- though realism would apply here, too -- the Shi, the Enclave, New Reno make sense in a game set in the close aftermath of the apocalypse. They should be
before FO, in other words, not after it. "Surviving remnants of the central government try to maintain power from an oil rig with the last scraps of the old-world military" is classic
near-post-apocalypse story. It's not just that it's unrealistic to have them flying old-world helicopters off an oil rig 200 years after the apocalypse, it's that it doesn't even fit with the genre's themes. Same with the Shi. A submarine crew surviving the apocalypse and having access to extra vestiges of technology
is thematic (e.g., On The Beach). So the Shi would largely work in a game set, say, 10 years after the apocalypse (though you wouldn't have them
exceeding old-world technology). But they don't work two centuries out. At that point, their technology would be broken down; they might still have a few bits and pieces, and they could dominate their domain based on the benefits of starting out with a huge technological lead. But they wouldn't be engineering radiation-eating plants. That's not a thematically sound extension of the submarine trope. So too with New Reno. The city would be fine as a kind of grotesque Mrs. Havisham's-wedding-feast of a city -- spared nuclear fire, but collapsing due to broken supply chains, lack of government, starvation, etc. It would be thematic for such a city to be run by warlord gangsters, and to try to imitate the luxuries and vices of the past (gambling, porno, boxing, etc.) in rotting ways. But once you go two centuries out, it doesn't make any sense. The city would have totally collapsed; you might have a second-growth city in its ruins (like you had in Rome -- though I'm not sure that modern "ruins" would stay standing for as long). That would be thematic. But that's not what the game shows. The game shows silliness like intact sidewalks.
I think you missed the part where a not insignificant chunk of the world in FO2 is frontier running mostly 1800s tech and tribals going around with spears and knives. The primitivism is totally there.
To go back to where I started in my initial reply -- the point is that FO2 is not a "'slow', mellow, melancholy, nuclear apocalypse wasteland setting." It's probably the most cheerfully optimistic post-apocalyptic setting since Genesis 9:1-17. Everything in the world is
way better than it was in the first game. In a scant couple generations, technology is restored, the radiation problem is about to be fixed, trade is reestablished, a central government is back, etc. As you say, if one projects FO3 from FO2 based on how things went from FO1 to FO2, it would look something like this:
My bottom line position is that I don't think that's the way things would actually go and, more importantly, it's not the way post-apocalyptic stories are
supposed to go. What we are
supposed to see is that the old-world technology and old-world political structures continue to fall, and the question is whether the last of the old-world's virtuous strength (typically arrayed against the last of the old-world's vicious strength) can protect the green shoots of a new world for long enough for them to take hold. Then you see a second growth new world emerge, one that feels uncanny and alien (e.g., The Planet of the Apes, original or remake movies, same deal.) In FO2, we get the exact opposite: we go from seeing a vault that is breaking down to seeing a thriving Vault City; from seeing a very small number of people maintaining old-world weapons to great advantage to old-world weapons being in the hands of factions all over the place; from the Boneyard to New Reno and San Francisco. We don't see a single hint of regression
anywhere except for the tribals, which everyone gets annoyed about because they make no sense in the otherwise Great Leap Forward setting of FO2.
So, to me, FO2 should either have been set close enough in time to FO1 to just keep the same setting or, if it was going to jump forward a few generations, should have shown
further collapse of stuff. (Consider Mad Max vs. The Road Warrior, or the Planet of the Apes remake trilogy). It's perfectly fine for the NCR to continue growing (it's a second-growth society). But I would absolutely not have introduced faction after faction, and locale after locale, in which the old-world technology, structures, societies, etc. are in
better condition than they were in FO1.
Anyway, wasted a bunch of time on this, no one ever persuades anyone else of anything, but there's my take.