In Your Opinion, what is the theme of the Fallout series? From Fallout 1 to Fallout 4. I'm honestly a little bit curious since I've seen people saying a lot of different things about Bethesda's Fallouts not staying true to the original but in reality, staying true to a series is done via the theme, not how the actual games play. (This is why I generally dislike Tomb Raider 2013. It changed the theme of the Tomb Raider series).
I've never really gotten into the original Fallouts myself though, I want to try them sometime and hopefully will get to eventually. So I can't say too much about the originals, but I've read about them and know the ordeal that happens with them. (Or at least a bit. I've mostly read up on Fallout 1, than Fallout 2).
BUT... I feel that there's a similar pattern in the series as a whole. A theme, so to say. From the first one to the 4th one. It isn't necessary about war itself though but about the complexity of war and how easily things can change just by attempting to do a small quest, so to say. In each game, the main character journeys out into the wasteland on a rather simple quest. First one was about finding a water chip for their Vault so that their water supply may continue, which sounds reasonable. With 3 and 4, it's about just finding your father/son and trying to figure out the why. Again, a small quest idea and pretty reasonable. In New Vegas, the journey was about tracking down the guy who basically took your job and tried to kill you. Again, small idea and pretty reasonable. Who wouldn't want to have at least justice, if not revenge, on the person who took their job and shot them twice?
Here's the thing though, what happens when you finish this journey at the end of the road? What do you meet and what are you pull into? War. In the first Fallout, you ended up getting yourself pulled into a war between the Brotherhood of Steel and Super Mutants (AKA: The Master). I believe the second was similar but Enclave instead. Third one again, was similar (BoS and Enclave over the water purifier). New Vegas and Fallout 4 though, it was a war between four factions for who should control and protect the Mojave/Commonwealth.
In each game, it seems like the MQ is about the big picture of war and how it can easily effect us all, even if we weren't aiming for it original. We can do something simple like finding a missing family member or that guy who tried to kill you but you can easily get pull into the bigger picture of what's really going on. The current war going on between these large groups of people, and learning about the after effects of what you've done within the bigger picture. Which is probably why the games' quote is "War. War Never Changes."...
Anyways, that's just my 2-cents on what I feel is the Fallout theme. I've noticed some people have different opinions and thoughts, so am curious to hear what you say.