Generally, rich people are the ones that gambles a lot. Some poor people gamble too but with limited volume and are mostly betting with their friends and locals. Some countries like Singapore imposed high entrance fees on their local citizens when entering casinos.
I don't know anything about Singapore but you are very wrong if you think poor people don't gamble as much as rich people.
It is the exact opposite and I mean It.
Poor people in my country, they don't know how to stop. Actually I suspecting that they don't know the meaning of the word "stop". They'll play till they lose everything they got and they'll be trying again the same in the next month after they find new money and this goes like this forever.
Rich people on the other hand, they gamble for fun. They exactly know what they are doing and how much money they will be losing. They know when to stop and that's how manage to stay rich after the game. Gambling is just another way to spend time for rich people. It is like paying for watching TV or a movie. They know they won't be getting any richer by playing, they just want to pass the time!