Wealth hoarding is mostly a hyperprophied survival instinct. The rational person would optimize for happiness, not wealth. The connection between those is not linear, see: http://blogs.wsj.com/wealth/2010/09/07/the-perfect-salary-fo...

Also helping other is a significant factor in emotional wellbeing.

I mostly blame the current snapshot of evolving social system, not the actors, even psychopathic ones.