How can a person realize that a particular thing doesn't bring "happiness" without personal experience?

Buddha was, if I'm not mistaken, a privileged prince with money/health/a social life who realized that none of those things make you “happy” (or even content enough). But how can, for example, somebody who has only known poverty all his life attain a true realization that money won’t make him “happy” without firsthand experience? Or, how is this poor person to realize that money won't make him content when he is constantly bombarded with "evidence" of the opposite, after all, most people with more than their basic needs covered (I mean people of average economy, not the filthy rich) are content enough to not seek a means to end their "suffering".