The reason there are so many self-help books is not just that so many people are sad and searching, it’s because there are so many kinds of selves.
You could argue that there’s nothing new in this book or that book, that it’s all been said before. But this confuses an abstract idea’s having been expressed with the many ways of saying it. Sometimes a particular way of saying it, or of presenting the ideas, or some example, just hit home, and you get it. But your best friend might not get it in that same way. At a different moment in your life, even you might not get it that way.
It’s like why there are so many musical recordings. At some level, it’s all the same, all been done before. But sometimes a particular performance just hits you, and maybe it doesn’t hit your best friend at all, and it only hit you because you were tuned to it at that moment in your life. Playing a tune in your way, or writing a book, essay, or even a blog entry your way, maybe will hit somebody that was never hit before, even if they’ve heard the tune or the abstract concept. And it will stick with them and maybe make a little difference in their life.
It all has to do with the great variety of selves out there, each of which changes with the years and “the seasons of emotion”.