Authors in the commercial fiction world never have to worry about readers: they, and their publishers, worry about sales. If the book is sold to a customer, the author literally would not care less whether the person puts it on their shelf (many do) or reads it, because the book is sold and the author and publisher have benefited from it. It isnt really any of the author's business how many people actually read it. Presumably, however, having spent 8.95 or 13.95 or whatever the going rate is for paperback or hardcover books, purchasers are going to most likely read, sooner or later.
Fan fiction is free, and like many free things, is not valued the same as items people pay for. And reading is for the pleasure, or for the motivation - such as looking for a new and more hopeful ending, immersing oneself in a future where Jack doesn't die and he and Ennis make a happy life together, a telling of BBM that involves far more explicit sexual descriptions for entertainment value. Whatever it is, people shop for it, and they do so mostly by word of mouth.
For whatever peculiar psychological reason, there are really only two kinds of readers of the "Laramie Saga": those who love it, and those who start reading and drop it lilke a rock. I have talked with a lot of people about why this is so, and haven't drawn any hard and fast conclusions, except that AU fiction that posits a happy and sex-filled future in a safe haven for Jack and Ennis are the preferred reading of most fan fiction writers. For those who prefer to read the original ending and stick with that, they also tend to prefer fiction where Ennis works through his grief and pain without substantially improving his lot in life, and without finding another lover. These are popular tastes in the fan fiction world.
I didnt write this saga for those people. I wrote for those who, identifiying too closely with Ennis, and feeling a gaping wound left at the end of the film or story, have to complete the story with a plausible future outcome for Ennis and a step by step resolution of his losses and pains, and doing so in the context of a new, healthier love relationship with another man. This audience is people who need to have a mirror for the kind of change they personally would like to accomplish for themselves - and not everyone wants to do that, and as we well know, not every fan fiction reader wants to see that unfold in a story. So without sounding smug (No, I don't believe that those readers who want to move on are better people... just in a different place with respect to the original story/film), the Laramie Saga is for a specialized audience. Like Brokeback Mountain itself - it does not speak to everyone, and it will leave many readers who fell in love with BBM - completely cold.
That's okay too. While it is patently unfair to write something off that you haven't read... readers of fan fiction get what they pay for. And any time they feel they didn't get what they wanted in my story --- they are welcome to ask for a refund.