Some guy in a post apocalyptic environment could pick up an old history textbook of Riddler and decide to run his own national socialist group, thus creating national socialists all over again.
That's what caesar did in NV. He's basically some guy that read some history books.
It's all about the region.
With all the castles and revolutionary stuff you do actually see some people trying to reenact it in Fallout 4 but it's not as heavily emphasized as it should be. Hanrooster, the minutemen and captain ironsides is one of the bigger examples.
They just aren't as fully fledged out as they should be.
Maybe that's why you like NV so much since that was practically a western with lasers.
You see a "western with lasers."
I see a post apocalyptic environment with inhabitants taking advice from pre-war western billboards and tv shows around the area.