what we win is the money we lose, I don't think so, I think when I win gambling it is someone else's money who loses and vice versa, and this cycle will continue to turn, and that is the reason why casinos very rarely go bankrupt because they pay out their winnings. which is greater than their income
Before a casino would be approved and licensed, there is this body that make sure that the company is insure before they commence operation, it's one of the safety guide to protect players and if that money is not available, they don't licnence the casino. However, I'm not sure if most of these casino do something like that before they commence operation but even at that, there must be money set aside huge enough to pay people that may luckily win big amount but on the long run, if there is more customers they should have increased in gross revenue.
When you lose, the money goes to the gambling and the casino becomes the real ownership of the gambling and when you lose, you didn't win money of others, it's the money of the casino, they are the one paying you from there money and not from the previous people that has lost due to change in ownership of the money.