The reason I am recommending this excerpt from All Things Considered by G. K. Chesterton is not because it says something that nobody else is saying today. But because he said it over a hundred years ago.
There has appeared in our time a particular class of books and articles which I sincerely and solemnly think may be called the silliest ever known among men. They are much more wild than the wildest romances of chivalry and much more dull than the dullest religious tract. Moreover, the romances of chivalry were at least about chivalry; the religious tracts are about religion. But these things are about nothing; they are about what is called Success.
So it turns out that self-help books and their nothingness are not a malaise that has appeared only recently. And nor is the need to caution people against them particularly modern.
So if you are not convinced against self-help books in modern way and would rather partake some ancient wisdom, read The Fallacy of Success by G. K. Chesterton.