Let it be known that BBeast is my favorite person as of now.

Anyway, my argument isn't about the existence of any advanced weaponry, but of it's availability to a WRECKED city that only allows authorized military personnel in and out. The norm for weaponry before the Void Opening was flintlock and revolving chambered weapons, or nonlethal core-based weapons. In the course of one year, after a massive cataclysm, a huge governmental shift, and likely a gargantuan economic shit, the mass-production of ANYTHING would be hard to do. Even if the military suddenly thought up automatics, plasma rifles, or whatever,it would be difficult to make enough for all their soldiers and then lose them to a bunch of street gangs. If the street gangs made the shit up themselves, it'd be pretty crazy to be up against that and not be freaked the fuck out (see "Legolas with a sniper" example; orcs would be shitting themselves). 

As far as technological advancement in general goes, the evolution of firearms from one-shot, black powder guns to magazine-using, full-auto rifles took hundreds of years. That whole time, we WERE in war. Also, the technology in Aeros was massively inflated by cores, just as modern tech has been inflated by fossil fuels. If suddenly we ran out of oil and coal, or if Aeros ran out of cores, everything would go to complete shit. You can't just credit the fast development of shit to "well all their stuff is futuristic, so it wouldn't take much to catch up weaponry". The only reason everything is so advanced is because of the aid of CORES.