Well, let’s start off with two assumptions you just pelted me with that I want to question.
First, why in the world should porn stories be any less “stories” just because they are erotic? Is there something about including porn that necessarily makes them bad? Or is the audience’s standards so low, or so base, that the addition of a good plot and strong characters actually turns them off? If the former, I’d be really curious to know how something like Game of Thrones gets critical acclaim while including all of that “porn” in there, and if the latter, then that’s not really an audience I’m all that interested in supplying content to, and I’ll wait around for a different audience who might like a decent story to go with their erotica.
Second, characters in stories are never real people. But there are good characters and bad characters. I would say that good characters, in addition to having more complex motivations and being better able to foster an audience’s sympathy, are also capable of having much better, and more interesting sex, than bad characters. Why wouldn’t you want better characters in a story? I’m not trying to write real people here; none of this stuff can happen in real life, so why would I bother with real people. But better characterization? That’s something I can get behind.
Now, dispensing with those two assumptions which I disagree with, I might rephrase your question as something like, “Why should an author bother writing good stories with interesting characters when the primary reason people read these stories is to ‘get off’ (an act which presumably does not require a good story or interesting characters)?”
Well, that’s because I’d like my stories to do more than get people off. Granted, I do like getting people off–I have no intention of stopping that side of things. But maybe stories can also make people think. Maybe they can also have character’s they relate to and sympathize with. Maybe a story can be more than a neutral mask indulging in a variety of sexual experiences and physical and mental changes. That’s what I want to write at least–that might not be what you want to read.
That’s perfectly ok–if that sounds like an utter bore, than go read some other stuff–there’s plenty out there. But I’m going to focus on writing what I want to write–I’ll trust that an audience interested in what I have to deliver will find me and enjoy my stories.