>>282216638
Not that anon but it's pretty much this.

They have recognised which combination of tropes + visuals will get the most interest, and just reiterate the same plots over and over because people buy it up. The amount of BL stories that give bingo for shitty story telling conventions is awful. But the chart can be adapted across all genres and media types- the more expensive it becomes to make entertainment, the less risky publishers and studios get with what they are willing to bankroll.