I think it's not the specialty of anime makers, as you say. vampires, robots and killers, much gore little romance.

When you said that most romance anime place their stories in school you reminded me of an anime that I saw many years ago by locomotion called sakura mail, was just the story based on 2 cousins who did not know they were and were studying and at the same time falling in love, of course until they realize and nothing else happens, by the way the anime was romantic but the category was soft-hentai so it was not so romantic if not that I entered into sexual grounds but very subtly.

I think it is to force the situation within a violent market romance has no profitability, I will look for some of the animes that you have cited to see them.

thank you for sharing, greetings