Well, there are exceptions. I have seen a rich gambler go bankrupt while trying to increase his or her fortune through gambling. Sometimes the rich believe they gamble for fun and then gamble uncontrollably until they become addicted and lose everything. This demonstrates that even the rich are susceptible to addiction if they lack self-control. Thus, regardless of the reason for gambling, whether poor or rich, it is imperative to adhere to a time and resource budget.
Maybe their daily lifestyle also affects their decisions when it comes to gambling.
I mean if they're rich, but kind of frugal then I guess that might affect their decision and instead of playing more despite them earning that much, they still end up losing and get bankrupt.
It's also not the rich that have this kind of thinking that they are wiring their minds that they will just gamble for fun but end up gambling for money. I've also seen some average and even poor guys here in our community. I've heard them saying "They will just gamble using X amount of money - just for fun." and when they ended up winning consecutive times, they gambled even more and their main reason which is gambling for fun ended up gambling for money hence, they ended up losing their money.
Anyway, it all comes back to decision-making. Lack of self-control, lack of discipline, can't be contented. These are the problems that most of the gamblers have whether they're rich or poor.