I don’t know the answer to this, but I imagine one of the factors at play is that most used book retailers are flooded with copies of popular classics. If I didn’t already own Middlemarch and wanted a copy, I’d head to my local used bookstore and get a copy for ~$3/4. The fact that the authors for classics are no longer alive means I would always go for used copies over new.
So the number of copies that are being purchased and read includes more than just how many copies Amazon is selling new. Also, I wonder how this metric is arrived at. Because if ~10 copies of Middlemarch sold per day is just reflective of one of the many, many editions of the book available on Amazon, then I could see it. But if it’s all editions of Middlemarch, then that does seem a little low. We’re talking about the number one book retailer in the world.
Full disclosure, this is a response to the same question, that I wrote and am copying here:
It’s one of the best novels I’ve ever read that deals with the theme of the sins of one generation passing on to those that follow.
When it appears in pop culture lists, it’s often as an example of a great tragic love story (Catherine and Heathcliff), and that’s not unimportant to the story, but I find a lot of other things to love about it. I love the isolated feel of the houses on the moors. It creates a stifling atmosphere – as much as they’re situated in this wide open wilderness, the small handful of characters, all resentful of each other, are tied to this home and this twisted heritage.
I first read the novel in highschool, and I remember at the time, that it was one of the first novels I had ever read that really explored the grey area between right and wrong with its characters. None of the characters come off as thoughtlessly evil. Well, maybe Joseph does. But otherwise, they all have very well-defined motivations, and you can trace all the malice backward as you read.
There was also some fun to be had for me, in taking the picture of the present that we’re given at the beginning of the novel with Lockwood’s visit, and then jumping back with Nelly’s recitation of the past to kind of fit the puzzle together. The novel’s a study in patterns, imo. Most of the characters are shown as children at some point in the book, and you follow them all into adulthood, seeing each one gradually poisoned, and desperate that someone should escape alive. And then at the end, with Cathy and Hareton, it’s a real image of rebirth. One of the few hopeful, happy endings that has stuck with me as feeling completely articulate and genuine, whereas most feel either sappy or dishonest. You’ve gone this whole novel watching the story of a haunted house (haunted by spirits, but also by the living) play itself out, and it’s finally been cleansed. It’s a super well-earned and satisfying catharsis. But the possibility of unquiet slumbers still casts a shadow; I’m always partial to a well-placed note of uncertainty at the end of a novel.