I might be wrong with this, but if I remember correctly much of the stuff you saw in Fallout 1 and 2 was actually supposed to slowly fade out and simply dissapear.
Take the Brotherhood of Steel, Super Mutants, Ghouls and much more. A lot of those became less important with Fallout 2. It's Fallout 3 by Bethesda that decided, that everything has to come again, because Fallout is now to the masses killing radiated Zombies to 50s music with nuclear catapults.
How does it not make sense when all are powered by nuclear engines?
Why isn't the power armor exploding in a nuclear mushroom cloud? Or any weapon using micro fusion cells? Or anything else really that has something to do with it.
The reason is simple. It only happens, when it's convenient. When it adds to the "funn house" that the game is supposed to be in Bethesdas mind. That's why the player has not to worry about his power armor going critical with to much damage - or those from enemies.