A semi-quick note on worldbuilding realism versus narrative realism.
(This is gonna sound like I’m about to defend a specific crappy thing about The Magicians, but I am very much not. Quite the opposite.)
Worldbuilding and narrative realism are often treated like they’re one and the same, like one depends and/or reacts off of another, when they are two very different parts of storytelling that exist parallel to each other.
Worldbuilding realism involves the inner workings of the fictional world that has been specifically created for the story at hand--fairies, witches, everyone is blind, soulmate AU conditions, werewolves, aliens, etc etc. So long as the rules of the world are logically followed (despite involving illogical creations), the reader will be happy with whatever you can come up with that makes sense within the established framework. This is why The Magicians gets away with all of its whimsical bullshit, because it has been firmly established that this is a fictional universe where whimsical bullshit happens every day.
Then there’s narrative realism, which is an entirely different set of rules about which events will feel natural to the reader, and what will feel forced/contrived. This realism is based more in our real world experience--nobody would believe a lie that gets told so badly, the lovers oh-so conveniently have an hour to themselves, the villain just so happened to look the other way, etc etc.
The result is that you can have fantasy and sci fi stories feature completely made up creatures and technology that people readily accept, but can get called out about story beats that were obviously shoehorned in and felt too convenient. This is based on Aristotle’s rule of impossibility versus improbability, how we will accept the impossible in fiction (vampires) but not the improbable (the news featuring something relevant to the protagonist).
So when fans say they wanted X to happen between two characters, but the writers explain it wouldn’t have been realistic, going off about how “the show already has fantasy worlds and talking rabbits what do you mean realism” is missing one of the fundamentals of storytelling. The existence of water nymphs and the odds of two characters finding each other on a battlefield of thousands are two entirely separate issues, and no writer worth their salt will listen to you if you try to make it the same thing. (Conversely, this also means those fuckboys who try to tell you to ‘turn off your brain and enjoy the stupid show about space pirates’ when you try to point out unrealistic events are very, very wrong as well.)
The excuse that Quentin and Eliot could not have had a reunion because it was unrealistic is still bullshit, because the writers blatantly demonstrated in other areas of the show that they couldn’t possibly care less about narrative realism. An example (one of many), is how they kept Margo from running to save Eliot just to make sure she was conveniently around to reunite with Josh. They bent over backwards to make that happen, and selectively saying these other two characters couldn’t have reunited because they suddenly cared about narrative realism is 10000% bullshit.
TL;DR - Yes, John and Sera’s explanation for there being no Queliot reunion is a weak-ass excuse to cover their misstep in service of almighty sUbVeRsIoN, but not for the reason everyone seems to be saying.