Despite the vast quantities of domestic!AU fanfic that exist to the contrary, there’s still a common misconception in TVlandia that romantic relationships are only really interesting when imminent or imperilled; that any sort of emotional contentment or continuity between the characters will be boring to watch. And yet platonic relationships, in which we’re also meant to invest, are just as frequently treated as rock-solid: inviolable except, potentially, at a few plot-critical junctures. And that’s a big problem for romantic pairings – or rather, for our ability to invest in them, because the plain fact is, you can’t successfully threaten to destroy a thing you’ve never committed to building. Not only will nobody care, but there’s literally nothing to tear down except your own expired eviction notices. When you make it your telegraphed aim, week in, week out, year after year, to perpetuate a will-they, won’t-they dynamic, it becomes increasingly hard to give a shit about the won’t-they episodes, because, just like a child threatening to run away to the circus, it doesn’t matter how loudly you scream And this time, I mean it! – we all know you’re bluffing.
Having gone this route, the writers then wonder why fandom is often far more invested in seeing those platonic (predominantly male/male) relationships become romantic than in their canonical (predominantly male/female) pairings. Which: yes, we want queer representation, and yes, we enjoy our own interpretations of the characters, but at base, the problem - as far as you TV writers are concerned, anyway - is trifold. Firstly, you’re limiting your romantic male/female interactions to fit a preordained narrative, which paradoxically weakens the same relationship they’re meant to promote by shallowing its development. Secondly, because you’re worried portraying a platonic male/female relationship in addition to your romantic one might confuse viewers as to who, in fact, the girl is meant to end up with, you don’t create any extraneous narrative potential between characters of the opposite gender. Which means, third and finally, that your same sex interactions are likely biased towards male-male, as most shows tend to have fewer female characters overall – and when they do appear, as per the first point, you’re usually orienting their participation around a single particular man, instead of letting them talk to each other – which means the most naturally developed, complex relationships portrayed are, overwhelmingly, between men.
Thus: having firmly invested your audience in the importance of a romantic relationship, you then proceed to use all the juiciest romantic foundations – which is to say, shared interests, complex histories, mutual respect, in-jokes, magnetic antagonism, slowly kindled alliances and a dozen other things – in male/male scenes, and then affect gaping surprise when your fanbase not only notices, but expresses a preference for it.