No, that's precisely what it is Teri. I think marketing as well tends to homogenize books even if they aren't necessarily that similar in order to play to a particular audience or keep their books in line with a particular trend. But ultimately, I think that publishing (or rather big publishers) narrow the scope of what can be published by adhering to the assembly line process - acquire books with X, Y, and Z elements. It goes far beyond simply genre. Often books are acquired because they have specific elements that are familiar to those found in the Big Books that Sold Colossally Well - ie) the kind of protagonists that star in the books, the kind of voice and POV in the books, the relationship the protagonist has with his/her love interest(s), the characterization of the love interest(s), the plot structure, the threat, the kind of supernatural/non-normal elements in the book etc. It's not just dystopian books being sold, for example, but certain KINDS of dystopians with certain KINDS of sensibilities and characters and interactions. Because of that, looking at publisher's marketplace, or at goodreads (particularly at the books being distributed by Big 6-ers) can feel like looking at one of those mirrors where you see yourself seeing yourself seeing yourself ad infinitum.
It's maddening as a writer, and as a reader because of course I'm looking for stuff that I HAVEN'T read before and they're hard to find. But it does leave an opening for other kinds of publishers who aren't chained to a kind of All or Nothing publishing structure where their hope is to sell big or go home (which means selling something that they think will do well because it's like other stuff that has done well). And people that are a little tired of the same old same old can hopefully go there to find something new and interesting.
I dunno. I think I've come to terms with publishing being that way, as well as with the fact that I might never catch the upswing or start a trend myself. I can't bring myself to write in a trend for the sake of publishing. Not yet anyway. I mean wtf do I know about mystery? Thrillers or dystopia? Nope. I barely read in the genres, so for me to suddenly write my ridiculous 'What If' scenario to try and get some cash...I mean I can understand why people do it but I don't even think I'd be able to. The only way I can write a good story is if I believe in the story I'm writing and I'm having fun writing it. And I think first and foremost people should concentrate on writing a good story.
I've also finally let go of the unspoken expectation in YA that one must publish big their first go around. I do think in YA especially there's that expectation - because it's happened before, we all want to write that debut that's going to be huge and hyped and widely distributed and become if not the next big thing then a Best Seller. Hell, now and days if you're a YA author and your book ISN'T optioned for film you'll feel like a failure, or at least a second-class citizen in YA-Writer world. That's part of what drives people, I think, to write what they think is 'in' or to catch a certain trend. But there's no shame in writing something different even if it means you have to self-publish it first or publish with a small press. People now and days are thinking of instant gratification, EVERYTHING RIGHT NOW, when perhaps it's better to think long-term - how do you want your writing career to be? It's alright if it starts out small. And if you want to go big right away, what kinds of concessions are you willing to make to ensure that happens?
Sorry I'm rambling again....