Omg, this is so fascinating, and just what I was thinking about while struggling with my recent fic. It's my first time writing for DTH, and I admit that in my darkest writing hour, I kinda cursed the fact that the fest even exists, haha. It took me a while, but I eventually worked out that the problem I was having was the stipulation of the sex. I have always written D/H as switching - although I do tend to lean towards bottom!Draco - and I don't really think about the sex scenes until I get to them. So having that stipulation in the back of my mind was a real stumbling block for me. So yeah, I had been sitting there wondering why DTH was a thing when a HTD type fest isn't, so it's really interesting to learn how that came about.