So, what's the message we're supposed to get from the Fallout series? Well, it's right there in the intro sequence: "War... War never changes."... But was does that actually mean? Does war really not change, or is it the manner of which war is waged that doesn't change? What's it all about?
Fallout as a world isn't just a setting meant to be the framework on which you make other, smaller and selfcontained stories; it's a setting that wants to tell a story right from the beginning. This is unlike a setting Warhammer 40,000 (a similarly pulpy and retro-futuristic setting), where the world never changes, because that would ruin the setting in which hundreds of stories are taking place at once - it's just a vessel for other, individual stories. But Fallout couldn't be further from that. Fallout, as a series, is about change, how people reacts to changes thrust upon them, and how they deal with the ability to facilitate change themselves. All games in the series feature these themes at their cores. Yes, there are stories about lost sons, exile and suave men in checkered suits that seem the most apparent, but those stories are only the stories told about or protagonists - No, the real protagonist of the main story of Fallout is the US Wasteland itself.
In each game, the player wanders a wasteland, or rather a part of the wasteland, which is in the middle of some sort of schism that throws it into turmoil and heavy changes; and if it isn't immediatly apparent when you start, your character is sure to bring that change. In each game, the player has the ability to join several factions, help wastelanders and eradicate scores of evil mutants and Raiders, something very few other characters in the setting does. So, no matter what, when the player leaves the wasteland, they've changed it, and brought about changes for the people around you. The most obvious case of this is between Fallout 1 to 2, where the western wasteland has become more civilized, since the player did something about the Master's army in the first game. Then, in Fallout: New Vegas, the player will encounter the NCR, a state that the player brought about earlier in the series. Let that sink in for a moment - Because one guy became a hero and blew some mutant army up (and did a load of things on the side), a damn STATE was formed, civilizing an entire former US state! That's huge! You've been changing everything from the start off! How's that for "Never Changes", huh?!
But that brings up an interesting question... Why doesn't war change then? So much has been changed by so few people, so why doesn't war change?
- Because, in the end, people have to fight over resources and ideology. War is going to be a constant so long as people disagree. You're changing the stage curtains, not the play. It's worth noting, though, that Ulysses makes a claim that even if war never changes, men can change.