For the rich and wealthy, gambling could easily be something done out of fun or leisure but, when it comes to people who see it for a means of earning there daily bread, it easily feels like an only chance or means to a survival.
Sorry if I didn't get this right, but are you suggesting that reach people are more immune for addiction? If my interpretation is right then I have to disagree with what you said. I don't have exact numbers but I believe it's actually the opposite which is right. Wealthy people are more prone to all kinds of addiction not only gambling addiction. They spend more time playing because they can afford to do so which makes them subject to addiction and they won't realize it till they start running out of money.
Yes, it's true that addiction doesn't choose even rich people or poor people, sometimes there are also rich people who go bankrupt because of gambling because of their addiction, middle-class people usually play gambling just for fun, the same as rich people, but that doesn't mean playing for fun. not be an addict. because if you play uncontrolled you will eventually become an addict too.
Most people from the lower middle class become addicts more easily because they usually gamble for money and spend their time gambling. Even though the rich have more time to gamble, it doesn't rule out that everyone can't become an addict, it all goes back to how we control ourselves and regulate our mindset when gambling.