Gambling is basically paying for chasing the fantasy of becoming a millionaire, which they already are.
I disagree with you on this, that people are gambling to become a millionaire, and that millionaire do not gamble because they have millions. People that gamble to become millionaires are always those that think they can make a fortune through gambling, which it do end up to be the opposite, and they are not responsible gamblers.
There are another kind of gamblers that do not gamble because they want to make millions, but they gamble for fun, because they have come to understand that gambling is a game of luck and should be seen as a means of entertainment. Such people are the ones that are enjoying gambling, and we have both the rich and the poor falling in this category.
I have heard of some millionaires that gambled and became broke. So what were they looking for when they already have millions. Addiction a problem to all, both the rich and the poor.