Peterson's main "self-help" message is to take responsibility for yourself and do so by finding something meaningful in your life that will facilitate the adoption of that responsibility. So perhaps people who have wasted opportunity and are floundering in the world are more likely to need "advice" than someone who has their shit together, and are therefore more likely to respond positively to Peterson's self-help messages.
All of my Peterson-listening friends are highly successful. Not because of him, but what he says resonates for whatever reason.
That's my general impression as well. Peterson was in my city a couple of nights ago and it seems that a vast majority of people who attend his talks are normal people interested in his critiques of identity politics, gender relations etc.