I was starting to think the same thing, after a certain point the whole "post apocalypse" will give way to a reconstructive period. I do think that they rushed the timeline a bit, nuclear fallout would last possibly thousands of years before dissapating this much, but they seem to have technollogy capable of speeding that process up, so w/e
Think of it like the post-classical era, the nuclear war being the fall of rome. After society's collapse there was chaos, and little groups of people banded together again to try and reform their nations. As they grew they began moving steadily away from the ruins of the old and into the middle ages and eventually the renaissance. That's where the fallout Universe is right now, just after the classical age and beginning to form a new and better world. One of the major reasons I didn't side with House was because he would only have set the world back, kept them all in the period of distrust and hatred of the old. He would eventually be the wrong choice. After the fall of Rome the Byzantines, still self assured of their dominance and the grandure of Rome, along with being sure they couldn't fail and would never fall into the same pit falls as they had in the past, fell apart because they didn't move forward, but I digress.
Fallout will eventually have to end, and they will most likely end it with a second great war that begins the cycle anew and the same message conveyed over and over; that war never changes. The next Fallouts, if they are to stay in the same Genre, will have to take place in an entirely different area of the world/ U.S., one that has not yet been civilized. I'd also like to see a return to the East coast, but that's just me