The kind of books that sell, and manage to still sell, are books that communicate timeless truths in a universal way.
No author wants a flash in the pan kind of book.
They want a book that gets better with time – a Perennial Seller.
This is the desire for blog posts too, actually.
Bad books sell; people have bad taste. Bad books don’t sell; people prefer great books. Great books sell; after all, they are great. Great books don’t sell; they are too great to be understood. Great books sell only after their authors die. We’re comfortable with all of these clichés even though they can’t logically coexist.