Saying that Zero
did develop and that "personal development" therefore is for poor people to is frankly speaking poor reasoning. The term "personal development" is referring to not only the process but also the means - the books and so forth - and obviously these were of no help for Zero.
I think you, Zero, have drawn a correct conclusion. It is not for poor people. Instead it can be harmful because it only delays work on what is _really important - making friends, getting therapy etc.
I know it because I've been there. And I don't think that many motivational speakers have. Both (two examples) Steve Pavlina and Tony Robbins, when talking about their worst periods in life, are talking about circumstantial things. 1. Being addicted to stealing etc. 2. His father leaving him.
I would bet my bankroll that none of these gentlemen have been clinically depressed for example. It is impossible, because some (some) of their beliefs would appear "a bit" naïve with the knowledge gained from that experience.