SF asks a lot of readers in the grand scheme of things. The limits if any are within the imagination of the writers.
It is an evolution in the writing process that goes hand in hand with the day and age that we live in. Very much like the TV and movie industry.
Look at old TV shows and we see space ships that look like either discs, or rockets propped upright on three large tail fins. Special affects included a bunch of smoke and sparks coming from the rear of the ship as it made its way slowly into the sky.
Remember Flash Gordon. The affects were part of the sign of the times. It was years later that Star Trek popped up. Things changed. Affects looked better and seemed more plausible.
Today Battlestar Galactica, Star Wars, Avatar, and others share with us incredible realism of affects. Plausibility increases.
But in the same way that our technology has made for better and visually more appealing entertainment it has also made books more subject to scrutiny.
If you were not an expert in medieval castles or a history buff, and you read something that seemed a bit odd, in the 70's you could not pull out your smart phone and google it.
You had to ask around, go to a history teacher or specialist, or hit the library. It took more time to check things out than what many people cared to do.
But today the data is at everyone's fingertips. There is always going to be someone checking things that any author writes with a critical eye.
Whether its an oversight on the part of an author, a different perspective, or intentional breaking "the rules" there will be a critic or two checking or calling "foul" at times. It comes with the territory.
I think that the biggest thing is that an author establishes rules within their own system and sticks with those rules consistently, and then works on creating the best tale that they can.
Its easy to tear down Star Trek. Its easy to debunk or dismiss parts of this industry. Still its far more enjoyable to overlook it and simply immerse yourself in the plot or the story.