I don't know how many times we have to have this argument.
What makes Fallout- "Fallout"- is the sci-fi futuristic feel that comes from how Americans viewed the future would be in the 1950's. It's where the timeline diverged from our own. That's what makes the game unique. If you remove that aspect of it, then you just have Metro 2033 or one of the other millions of post apocalyptic games.
Do a 50's Canadian view of the future, and mix with American view? We could show the culture clash that was going on at the time. Would be interesting to see say... Toronto all done up with American propaganda and perhaps them even taking over companies, but in more rural areas seeing things more Canadian.
It can still be done while retaining that feel, it just sounds like an excuse to keep it in the states.
Alternatively redefine what a Fallout game is.
< Cheap smart ass answer.