I 100% agree with the general consensus here!
I will forever remember a comment on an anime forum that said something like "Instead of shipping the characters (in this cool action plot-heavy) story when they are obviously straight why won't you just go and read your gay comics instead". And this is where the main problem lies - the characters or the plot often isn't interesting or engaging enough for BL stories that people actually stick around to draw fanart/write fanfictition about it. I am a sucker for slow burn as slow burn is the closest to how irl (healthy) relationships develop. For me to like a character there has to be a significant amount of plot and backstory and I want to know about their likes, fears, goals, insecurities and how/if they overcome them. This makes these 100% perfect rich, successful, handsome, muscular I-only-top type of characters so hard to like. It just oozes of an unhealthy power dynamic when the other person is young, just starting out in life, clumsy, childish etc.
That isn't to say that I don't also read a ton of hardcore smut with zero or bad plot but I regard it the same as porn. Sometimes you're in the mood for it but most of the time you'd rather watch a cool tv series or read a book with relatable characters.