Lack of money is often the first reason someone starts gambling, either because life is hard or because they want to get rich fast. But without self control anyone can fall into it rich or poor. So the answer is maybe not just about having steady income, but also learning how to handle money and emotions well from the start, so people can stay away from greed something that can happen to anyone rich or poor. However, it seems the ones who get hurt more by this are the ones who lack money.
That's not the reason most times, I know people are facing hard times and lack of money could trigger them to start looking for shortcuts like gambling and ponzi scheme but what then can say is the reason why the rich people also gamble? are they also suffering or you think they want to make more money, to the poor they are looking for fast money that's why they want to gamble to make it very fast but to the rich greed is the only thing that makes them to gamble because if they are contented with what they have tou won't see them gambling for money they will just play games to have fun and move on.
To become rich is not the end of the road. If you ask the rich what their greatest fear in life is, most will say the greatest fear is to become broke again after tasting the sweetness of being rich. This is enough reason for some of them to double their money. I have rich friends who gamble. One of them dont spend his money on weekends. What he does is, before the weekend, he will place a bet on little odd of 1.60 with a big amount, and most times he wins the bet. The profit from the bet is what he spends on clubs and hangouts, while his capital remains intact.