I am going to speak mostly about Predator here, but I go to the local comic shop regularly (I have a pull list) and still see Alien & Predator everywhere. The Predator Essential Comics Vol.1 is eye-level as soon as you enter the shop on a graphic novel rack, and the new release shelf has copies of Williams Gibson's Alien 3 as well as some remaining copies of Predator: Hunters II
My local Target has a dedicated shelf with a ton of NECA Predator figures including the Bad Blood vs Enforcer 2-pack, Ahab , Fugitive and now the Thermal Vision Predator which I was checking out last night actually.
Basically, there's plenty of places the demographic in question gets exposure to Predator. Heck, just the memes alone riffing "Get to the chopper!" and the "You son of a bitch" handshake that circulates in young fan communities feeds general awareness.
It's like my super homegirl, Alien fan, The Sailing Rabbit. (I hope she doesn't mind me bringing her up). I believe she fits the demographic in question and she has never seen "The Terminator" or "Terminator 2 Judgment Day". But she knows what the Terminator is. And if tech noir cybernetic organisms was her thing, I'm certain she would be all over that. And I believe the same thing goes with Alien and Predator.