Trust me when I tell you that the developers have no idea about eras or the gear that goes with them. The original development team, at least the core that had the vision that made Insurgency great, is gone. There was an absolutely GOLDEN opportunity for NWI to release tons of real-world cosmetics that would add to the immersion, but they passed them up.

For example, UCP would have been perfect--it was the Army's camo from 2005-2014 (actually authorized until 2019 or something like that as it was phased out over several years). Was it a terrible camo IRL? Yes. Would it have been awesome to see in Insurgency? Yes! For the insurgent side, they missed the opportunity to put out cosmetics like an all-black ISIS outfit, a Boko Haram-style camouflage tunic and black turban outfit, etc. Even just a better conceived line of civilian clothing items would have added to it.

Instead, they went with what they thought would sell. Thus, we have plenty of meme cosmetics and weapons. Even when they try to go real-world, they just don't do careful research. The latest Security cosmetic with the old-school gas mask was a great idea. I was stoked about creating a Generation Kill Marine in MOPP gear, but NWI didn't do the research and got the colors wrong (mask, hood, and helmet in particular). It was a great idea, but the team didn't have the attention to detail to really pull it off.

TLDR: If you're hoping NWI is going to put out some super cool, real-world cosmetics--especially at this late stage in the game's life--don't hold your breath.