Perhaps true - but the advantages/opportunities associated with higher wealth/social status are significantly more likely to balance out sub-optimal personal development.

It's hardly a new idea, but one of the greatest advantages of wealth is the opportunity to take risks without feeling the true punishment of hard failure (regardless of whether those are professional or personal).

High water makes navigating the boulders a lot easier, so even if we assume that rich kids are less prepared to face challenges in life - on balance - that simply doesn't matter as much.