I think all this self help need for improvment really boils down to people are lost, feel lost
way back when everyone was mad on religion and saw it as a source of comfort and motivation and a guide to living their lives -- now with prevailing western logical mentality we all feel lost and alone in the world/universe so people look for the answers , for the meaning of life, happiness just to stop feeling so alone

and that is why books like that are mega best sellers because they preach the answer to loneliness.

the true answer will be revealed when science with quantum physics, religion god, chi, reincarnation all combine with some supreme genius developing the Theory of everything
which is just a matter of time and its all based around energy because thats what EVERYTHING in the universe boils down to