whatsy is extremely and wholly correct. i'm gonna add another thing to the pile, which is that repetition is necessary for recuperation. in order to convert the constitutive harm of structures/institutions into social narratives that can obscure their own second-order effects, you need to tell the story over and over again. sports is violence as entertainment; romance is marriage as entertainment. much of their overlapping* utility is that they are easy to consume, comfortingly predictable, and infinitely available. one romance novel can't flip marriage from the aforementioned patriarchal saw trap into the key to individual freedom *and* safety *and* happiness. a couple hundred thousand released into the cultural id...
with this repetition, the narrative fantasy (like gender, like genre) becomes a stable place you visit: sports is somewhere you can go where merit wins; romance is somewhere you can go where love saves somebody. what's striking about the rise of m/m sports romance in particular is that it raises the stakes of that fantasy even further--there is now somewhere you can go where THREE saw traps (marriage, violence, homophobia) become the conditions of happiness. i don't think it's a coincidence that as material conditions worsen, the escape fantasy becomes...more and more fantastic.
one more thing--much of sports romance's fantasy occurs via a specific elision of racism, particularly antiblackness. (sports in general do this much more transparently!) not a coincidence that hockey's the overwhelmingly white big 4 sport and also the locus of western** sports romance, particularly m/m sports romance. not a coincidence that the gays became repeatably consumable as desiring, deserving romantic subjects within the romance genre writ large before black people have. look at these goodreads shelf counts, and keep in mind that college-educated black women read more than everybody else, demographically:
romance as a genre is run by white women. consciously or not, the marriage fantasy these white women write over and over again protects whiteness more than it protects straightness. along this axis, the fantasy actually functions identically to the institution instead of transforming it. as the repetition of stories shows us, there's a hierarchy--social conditions that are onscreen, navigable such that 'marriage is good and a good marriage is possible', and social conditions that don't serve most creators' stakes in the marriage fantasy at all.
*for doing-my-real-job-today purposes i'm skipping some other very relevant overlaps between sports & romance--libidinal imaginaries, economies of ability and desirability, the temporal bound of a championship or a wedding, etc--but somebody else run w the ball pls
**i would really like to read some comparative scholarship on race overall in western romance and BL, if anybody has recs.