Frankly, the idea that these things just plain are not possible in a fictional universe is a bit hard to swallow.
That's not a good criteria for figuring out what's canonically acceptable for a fictional world. Consistency with the pre-existing background should be first among those concerns.
I hate to bring up the most obvious example, but: Star Wars universe. Eps IV-VI are fairly consistent (Ewoks aside) in terms of tone, 'scientificness' of the sci-fi elements, how much of Space Opera is in those movies, and so on.
Now, when we look at Eps I-III, a lot of those elements are missing, replaced by almost cutesy 'humorous' sci-fi and excessive references and tie-ins to the original trilogy.
Are the two groups consistent with each other? Hardly.
In a similar fashion, while Bethsoft can
say that their game is in the Fallout universe; put in all the names of the factions, 'creatures,' history and so on, their vision- tone, how certain background elements (such as nuclear weapons and radiation) are handled, and even how quite a few of the elements look versus how they looked in FO1/2- differs greatly from Black Isle's vision.
It's not consistent. Now, the fact that they
can be consistent with a spin-off (actually, both of the spin-offs; yes, the Enclave armor looks a *lot* like the FOT Power Armor) tells us, basically, what they've been projecting since almost the beginning of this project: they're doing 'what they do best,' and are ignoring fans' concerns about canon, style and tone.