This is a de-railing thread. Please, bring your problems here instead of hijacking other threads.
Then I'd suggest that you also refrain from "snippy" or "snide" comments as well ... and better reword that anonymous "hijacking"-charge as well, since particularly I only anwswered to something that was already there

You're the GM of your game, you explain it.
I just wonder how I am supposed to do that? Since you're obviously so keen on "artistic license", I'd rather hear your explaination, preferably one that answers the following questions:
1. Which obviously quite powerful faction (single entity or group), most likely with high magical ressources, would want the barrier to be brought down to either let something out or something else in and what is the motivation behind it, apart from the treasure hunt?
2. Why would such an entity be referenced in a book about "WAR!" and not in a book with a "Threats"-like theme?
3. If your explaination has something to do with a "WAR!": Where are the details for that?
You're right, it's not the GM's job to answer difficult questions about what happened to the various organizations involved in a four paragraph plot hook.. It's not like you play this game to be creative or anything. Look, sorry for being snippy, but seriously, you're complaining about being compelled to answer a mystery, last I checked, that's the job description.
Actually I don't believe in the honesty of you saying "sorry" there, so don't expect me to be polite from now on either. And no, it's not the GM's obligation to fill whatever can of worms a supplement writer opens. It's not my obligation as GM to answer questions about a more or less unamed, but extremely powerful entity that suddenly pops up out of thin air and puts (technically even heavy) focus on a region that was more or less a historical side note before. It's also not my obligation as GM to give such answers in the context of something titled "WAR!". I could be interested in giving such answers in the context of a "Threats"-like book, but then I'd surely expect more than a four paragraph "plot hook" to begin with.
And one of the big problems with your position that the GM is the one who has to do that job is the fact, that such large "holes" in the general gaming universe ultimately drive each group's universe far away from it, once an author finally finds the time and / or need to fill the blanks. I'm all for blanks on a low scale to allow individual character development, but holes within metaplot level are just terrible.
You're absolutely right, this is a pretty big break from the norm. But, how many years have passed? Isn't magic continuing to wax in the world, thus causing more unexplained phenomena?
The question is at what speed such events occur and of course again it's the question if such things should really come with a supplement that deals with "WAR!"?
Aren't all these kinds of questions things a gamemaster should be answering for his particular group?
That heavily depends on the implications a certain development has for the overal gaming world. In this particular instance we have to deal with mundane but still magically enhanced material. Something like that would be another holy grail for magical research within the gaming universe. Why stop with a standard stainless steel scalpel (that rusted anyway) if you could combine the effect with a vibro-blade? Or at the low end, why not try to replicate the magical improvements on ordinary things instead of using high-tech materials? While I might find an individual answer as to why the megas aren't swarming Auschwitz "right now" in order to find out as much as possible and certain megas surely not being averse of putting "innocents" under similar conditions that might or might not have produced thes atrifacts, those question would still remain unanswered for the gaming universe in general ... and that just leaves me with the question: Are they actually aware where they are taking this game?
Are you familiar with the terms "poetic license" and "alternative history"? Easy answer, maybe in SR's 5th World, the man was a little more hands on.
Ah, so now the divergence of the SR-Universe occured way before the prevously established time? Sorry, "poetic license" is far to often an extremely bad excuse for bad research and "peotic license" is usually given in places where style actually is better than substance. I find it rather hard to see anything of "style" in the whole section to award such a license. Your reference to an alternate history is additionaly amusing to me, since so many products of the current line (but also from the previous edition) tried to unmake the alreday established alternate history by introducing rather stupid copies of developments in our own world and in order to make it work even the crazy "Crash"-Szenario was invoked for a second time.
This one is a non-issue. After all, they've got a San Diego shipyard making aircraft carriers, and you don't hear me complaining that the naval yard there hasn't been in the "making" business for quite some time.
The question here is: Does said non-operational shipyard tag along implications for the metaplot once some ill-informed writer decides to get it back in business?
Nope, this article could have been better, but it also isn't something worth getting this bent out of shape over.
Bent out of shape? ~shrug~
I guess that accusation comes from the same end where the snippy parts came from ...