I still think it ranges from anarchy to developing nations at best. All the power in the Fallout world feels fragile and has many exceptions beyond its influence. This isn't really the sign of a developed society. I say anarchy because in real anarchy, you DO have pockets of organization with different idealogies, because anarchy in itself is a temporary state. Like in Fallout 1. The ghouls are a giant cult, there are large groups of wandering bandits, you have small farming villages, you have small closed-knit communities like Junktown, you have a small theocracy with the brotherhood of steel, you have merchants doing whatever in the hub. Everybody is doing their own thing, that's anarchy. In later games, some larger groups emerging, but they're warring and their hold isn't secure at all, nobody has obvious overall control, that may not be anarchy, but it's not really society either. It's more like warring tribes with more technology. As for the water thing, in addition to no almost no area in any of the games looking like it has remotely enough food and water to last for more than a few weeks, in Fallout 3 they say the water is radioactive and plant life basically can't grow, yet somehow this has lasted hundreds of years without everyone dead. To me that's just lazy writing.
Anyway, I don't really want to go further into a Fallout debate, but I'll say that Fallout feels squarely post apocalyptic, rather than dystopian. Strife to me feels dystopian. Post apocalyptic to me is Fallout, The Road, Road Warrior, Book of Eli, Walking Dead. Civilization has collapsed and hasn't really rebuilt yet. Dystopian is 1984, Brave New World, Soylent Green, Equilibrium, Hunger Games. Established society exists, but has clear oppression and / or very hollow or twisted values along with it.
Are you saying that because no one has obvious control over everything? The NCR has basically renovated the entire west coast, and has a very strong grasp on their territory, to the point where they're basically a modern nation, having their own industry, professional army, government, and even currency. Other clearly established societies exist, even if they tend to be small scale, like Vault City in Fallout 2 (seems pretty dystopian and is very high tech, well established, sell sufficient, and can swallow up surrounding territory) and the Legion (though, they may fall in to the "very weak grasp on power" category given that they basically disband after their leader's death).
I just don't agree with the idea that Fallout is really post-apocalyptic, at least not as of Fallout: New Vegas, due to organizations like the NCR, and the overall feeling of the world. Civilization HAS rebuilt, and the Mojave region doesn't seem any less civilized than the old west of the 1800s. The southwest and east haven't been seen for a while, but were well on the path to reconstruction last time we did see them. The west coast is entirely rebuilt to nearly modern levels. The Arizona/New Mexico/etc. area has been unified under a brutal, militaristic empire that, for the most part, is extremely low tech, but has random bits of modern technology dispersed throughout. The Mojave is the new frontier, and while there's no main government to it at the time, there will by the end of the game. The Utah region seems to be the only place we know of that still seems somewhat anarchic, being dotted with civilized city-states, such as New Canaan, but mostly inhabited my independent stone-age societies that just so happen to have found modern weapons.
Well, Fallout 3 is... Fallout 3. Kinda the black sheep of the series, and by far the least logical.
I don't think you should count Fallout 3 and onwards as the old Fallout series, it was built on the foundation of Fargo's Fallout but it had Bethesda's and Zenimax's dirty paw prints all over them. They are similar things but not the same game series continuing.