I don't personally think that wealth is actually distributed through gambling the only wealth that is distributed is going only going to the casinos money is going from gambler's to the owners of casinos which are business ventures apart from that there is no such thing as wealth distribution in gambling
You are right, no matter the process of money flow from casinos to gamblers vai pay out of winning, to the government via tax and also salaries paid to employees, the casinos still remains wealthier at the end and the money they distributed is not even more than 50% of the profits they make in a year. Gamblers are losing every day and that's how the casinos are making more money.
the casinos owners always