There is a lot of friction here that I don't understand... I mean, on the one hand you've got people saying the setting is starting to get too post-post-apocalyptic, and on the other hand, people who are saying that's how society would be 200 years after the war. The thing is, I don't think you guys actually have opposing view points; it's just a matter of opposing preferences. If you ask me, the state of humanity as of FNV not post-post-apocalyptic
enough for being 200 years after the war. I mean, look how far we came since the early 1800s; granted, you won't see nearly as much development in a post-apocalyptic world, but the fact that they've got robots to do everything for them should counter that at least somewhat, especially so close to the United States' one real center of civilization (that is, the NCR).

At any rate, if they keep moving the series forward, it's going to stretch credibility even more unless they focus on a part of the country that has struggled and failed to set up a functioning society/government (I'm sure there are lots of regions of the US that would have a lot of trouble with that after a nuclear war, particularly those away from major metropolitan centres). Either that or they could take us back in time a little; it's not like most Fallout games are in sequence except for the fact that they take place chronologically one after the other, after all.
Personally, I'm in favour of doing a little of both. Show us something new, first of all; I'm so tired of the NCR and even the Brotherhood to some extent. There's a whole lot of country out there besides California and Nevada, especially since the US annexed Canada. Second, take us back to something more like 100 years after the war, or maybe even less. It's already stretching believability to think that any part of the country should be so underdeveloped 200 years after the war, even nuclear though it was. You might find something, but it would be easier and more interesting to take us back in time and show us the burgeoning formation of new governments and regions, rather than expecting us to suspend our disbelief about why they're still so raggedy 200 years later.