You're arguing both sides. Either it is a fully thought through future world constructed by the filmmakers, or it isn't. When you insist that stuff doesn't make sense, you're saying that the filmmakers are so good that they screwed up their own vision, or that their vision is so bad that the resulting plot reveals them.
How about being a willing audience member that isn't some sort of expert in the future, and allow the filmmaker to have FTL without FTL coms?
It can't be fully thought out because different filmmakers are involved. That means a filmmaker can create something that works with the previous material or can't. That's needed because Ripley and W-Y appear in the three movies, and in prequels the same W-Y.
Also, my arguments are based on common sense, not that the writers screwed up their vision of the work. Here's an example I think I repeated earlier:
In the second movie, Ripley faces a board of inquiry that does not want to heed her request to check the coordinates of the landing site of the Nostromo to see if a derelict ship exists there. One of the board members, van Leuwen, explains that they don't have to because they set up a colony there two decades ago and it didn't see any derelict ship. What are the problems with this?
First of all, a board of inquiry doesn't pass judgment on an accused. Rather, it determines if there an accusation can proceed to a trial. In this case, Ripley is accused of destroying a company ship and its cargo for no valid reason, and there's no valid reason because her story about the alien craft, the facehugger, and the alien are all made up.
Second, the accused is innocent until proven guilty. That doesn't apply in absurd comedies or surreal films but not in realistic sci-fi. In this case, the only thing that Ripley has left to prove her case are the coordinates in the flight recorder log. If she had a lawyer, which should be the case in such proceedings, then that would be sufficient evidence for investigation. Besides, there's a colony with survey teams on the same rock, so it shouldn't be difficult to prove that (which is, ironically, what Burke ended up doing).
Third, van Leuwen's argument is wrong, and even a highschooler who took classes in reasoning could see through that: the colonists could have seen nothing because they didn't happen to visit those particular coordinates.
And this is just one of several discrepancies found in the film. It has nothing to do with taking both sides, or a vision, or predicting the future but what happens realistically.
Finally, how to resolve this issue? I think according to the
Weyland-Yutani Report, which is one licensed work, the company retrieved the flight recorder from the lifeboat (because it's their lifeboat) while investigators (likely, from the ICC) were scanning the boat "centimeter by centimeter" to find any organisms, and then deleted the coordinates.
And that's why the board couldn't honor Ripley's request.