I actually wonder if there is a term for all this... Protagonistic Centrism?
The problem with something like Alien, which was made to be a nightmare fuel thriller, was it created an iconic character. That sounds like a good thing, and it totally is, but it also causes people to get dragged into that character's orbit and the escape velocity for that is quite high. I don't think Alien would have had the cinematic impact it did have if Ripley had failed to survive, but it probably would have removed this case of Protagonistic Cetrism.
Ripley won, she has become a heroine, people latch onto that because screw the world, there has to be a winner and it damn well better be the heroine. Her survival was her victory, overshadowing the fact that she was royally screwed over by the events of the first Alien.
Aliens compounded on this Protagonistic Centrism by removing the real fear factor and replacing it with action and adding another awesome hero to orbit around as well as a cute and capable semi-damsel in distress which when added to the Ripley gravity well made a neat system with varied characters for fans to orbit around to their delight.
In comes Alien 3 and literally murders those characters without so much as a moments notice. The fans orbiting around Hicks and Newt were sent off into the abyss as their Centric Protagonists were snuffed out like a light. This is perfectly understandable, as one or two of the most important factors for some of the fans and the victory and stability carried over from the previous movie was shaken up violently from the get go.
The problem with the Protagonistic Centrism is that people often lose sight of the truly centric part of the whole franchise, which is the Alien itself. Ripley, Hicks and Newt, or any combination thereof, totally eclipsed the Alien and that's one of the reasons why the Alien is little more than zombie canon-fodder today.
The Alien is a body horror nightmare fuel space rapist that destroys everything everyone around it cares about or cutting them off from it. The Alien could be considered the perfect incarnation of the common concept of the Judaeo-Christian Hell, cutting off the main characters from all that is good in their world. It's cold, uncaring and, if going by the first movie, animalistically calculating and cocky.
Protagonistic Centrism can't thrive in a universe where the very franchise is the darkest and most violent creature in that universe. Fans of the humans are cast out, floating alone in space, screwed over by these creatures as much as Ripley, Hicks and Newt.
Protagonistic Centrics are out there, aimlessly drifting in their own Narcissus. Sucks, doesn't it? That's what the Alien does. Maybe the corporation will pick you up again, but what you'll get is a cold reminder of how cruel the universe is before being chucked right back into the nightmare.