In a world where readers face an unlimited quantity of high-quality low-cost works, the writers who achieve the most success will be those who take their readers to the most emotionally satisfying extremes. Books are pleasure-delivery devices.
And it’s not just applicable to the indie-/trad-pub divide; “why would I buy when I can get the fanfic for free?” is a madly common meme in fandom, too. It’s easy to blame readers for the attitude, but I think this is misplaced, particularly given that fannish readers are often looking for content that simply isn’t commercial available. Or, rather, historically hasn’t been; it’s starting to creep onto the (mainly virtual) shelves, but there’s something of a vicious cycle involved in that, if its target audience don’t know to look for it, they don’t find it, meaning they don’t buy it, meaning more of the same doesn’t get published.
Which is where self-pub and small presses come in, plus communities like GoodReads.