I know even 500 years after the bombs drop it will technically be a post apocalyptic world but what I mean is that in FO3 (I never played 1 or 2) I felt like I just came out of a hole in the ground to discover just how the world around me was destroyed by the bombs dropping with the wasteland, DC ruins and monstrous creatures created due to it. I didn't really get that same feeling from New Vegas. It was more of everything going back to normal and there you are just going about your life.
This is what was so weird, and made FO3 feel like a franchise reboot ~but wasn't. I played Fallout 1 and in the first game you emerge from the vault into an untamed remnant 50's retro world ~but its all the past. Those living in it now don't appear to
be retro 50's minded. It felt a bit like the [later] movie 'Blast from the Past', when Calvin and Adam leave the Vault.
http://www.youtube.com/watch?v=EXClAFX8N2Q
http://www.youtube.com/watch?v=8Z3N3KquVJY#t=01m20s
In Fallout 1, 80 years had past since the bombs. The world had shanty towns , inhabited ruins, and the Hub (somewhat like Barter Town in Mad Max).
In Fallout 2 80 years have past again and your PC lives in the a village that practically deifies their founder ~the PC from FO1. Towns and settlements exist all across the map. NCR sprung from Shady Sands and now has public utilities and a City Hall. Vault City exists (much as New Vegas), a gated community surrounded by slums. The Den in FO2 looks a lot like Freeside in FONV. Jacob's town is based on FO2's Broken Hills.
Fallout 3 takes us back to what appears like before FO1, and wants us to accept that mankind has lived in destroyed squalor for ten generations.
*(And FO3 adds supermutants and bottlecaps, and Enclave ~all of which were lost remnants themselves from the first two games ~and not appropriate for a game set farther in the future). Bottlecaps were given up by the time of FO2, they used currency, and made jokes about caps being worthless. DC has too much coinage to use sharp edged bottlecaps that don't stack as well as coins.
IMO Caps should have been left out of FO3 and NV. They are only in the games as an out of place tie-in/brand identifier.
"Remember Fallout?... Yeah my friend had it.. Its that PA rpg with supermutants and you used bottlecaps for money".