Most rich people are into gambling not mainly to earn money but for other reasons. Hence, they don't have the desire to gamble all the time. They usually select what game or sports they will venture into. In most cases, the sports they are passionate about. But for most gamblers in the middle class or poor, as long as they see good opportunity, they will bet on it.
But for those people who gamble just because they want to earn money, gambling will be detrimental to their small money left.
No way! I refused to believe your first paragraph. It's like you are saying rich people goes into business because they don't like money but because they just want to make the money, that's not true. Gambling is place primary for making money, any one can change their opinion but that's the truth and nothing but then truth. However, a rich person might be playing for fun and less motivation for money like the way a poor person would have in the first place.
If the casino are doing it for free, I'm sure they would by now be out of the he business, they are there to make money because they spend money on marketing to get your attention, they pay you when you win and they get paid when you lose and that's how it work continuesly until you either win them or you lose everything to them.