So: I used to read gen fic. When I talked about fanfic with my fan friends, I always said I liked the characters and the relationships. They continually tried to get me to try slash fic, and I would, I really tried: I'd find stories in the fandoms I was in featuring 'my' pairing and I'd try them ... and honestly, they were crap. I could not believe my fan friends were reading such poor quality stories!!
Then a friend sent me a gen zine for my birthday. It had three big stories in it, two of which were my big fandoms, the third some show I'd never heard of before, but I read the story anyway. And if was fantastic. I immediately wrote everyone I knew asking if they knew of any other stories, and another friend loaned me a different gen zine. Another long story, really really good I immediately decided that I was a fan of this show, the fic was great!
So I wrote my friends again and it was at this point that I found out that, somehow or other, I had managed to read the only two gen stories in the entire fandom - absolutely everything else was slash.
But I loved my new fandom so I decided to "tolerate" the slash - but it was good too!
It was much later, after going through more fandoms than I care to think about, that I realized that for most fandoms (though not all!), but that the really good stories in many fandoms are either mostly slash or mostly gen. So the gen fandoms I loved the fic on - I loved the fic because the good writers in those fandoms were writing gen. And the slash fandoms I got into - I lived the fic there because the good writers were writing slash.
Nowadays I wander freely back and forth, depending on what shows attract my interest. And sometimes I'll be reading gen and sometimes slash, but I end up reading one or the other because that's where the good writers in that fandom are.
Which is a really long-winded way of saying that, maybe it's the fandoms you're in that you're ending up with stories that don't interest you. It does happen!