I believe that the topic of self-development has been covered in its totality as far as content goes. By this I mean there is not and will not be any new concepts of self-development created. In addition to this, I believe self-development has been completely covered since ancient times. One can read the writings of philosophers and writers from said ancient times and find that many of their meditations on the subject are still novel thousands of years later. Furthermore, every self-development concept is not only known, but common knowledge in most societies. New works and ideas regarding self-development don’t concern the content itself, rather, illuminate ancient concepts in new ways.
Because of this, it leads one to believe that there are very few concepts in the field of self-development in as a whole. It is more-or-less a universal field, hence why we can even look to these ancient authors for illumination. Their revelations in the field are not affected by time because the human experience itself is besides time. The quality of their work is not necessarily derived from the content, rather, novel and innovative ways to relay it. There are hundreds of thousands of self-development books that seek to say a few things in many different ways. Even simple societal truisms like “hard work pays off” or “keep your head up” are the pinnacle of self-development but have been used to the point of cliché and therefore have lost their novelty. The clichéd connotations they carry hurt their ability to spark understanding, so their power isn’t respected, because surely the greatest self-development knowledge must be esoteric, right? It is sure that every single concept of self-development can be found in the societal truisms we hear every day.
The trick to self-development is not the literal knowledge of these tropes, rather a spark of understanding that allows an individual to completely apply said tropes to their lives with vigor. If self-development was as simple as merely knowing about it, everyone would be a master by merely hearing the clichéd tropes I’ve mentioned. The art of it is in the nuance—both how the message is delivered and how it is received. One may liken the quality of a self-development text to the quality of a teacher in theory—generally speaking, the difference between a good and bad teacher isn’t the literal information they teach, rather their ability to teach it in a way that the students will understand. On the other hand, a student seeking a true education (unlike in the education system in the United States, but I digress) will do their best to completely wrap their head around the concept in a way that sticks—not merely learn the information. In this way, to learn self-development successfully, both the text (teacher) must be competent and the reader (student) must be as well. In addition, exceptional quality from one party may partially make up for a lack in the other.