There are many roads to bankruptcy but I'd say it's a lack of competent management for a casino to file for bankruptcy. The market is large enough to accommodate a long-lasting business era for any established casino. I hear more of offline casino settings suffering bankruptcy. The expense of running a casino isn't a play. Only real management keeps casinos running for decades without a financial meltdown.
However, the success of a casino simply means the financial downfall of many gamblers. The question is, should gamblers win more and watch casinos go bankrupt? We'd lose our source of fun at the gaming level if that happens. In a nutshell, the money lost in gambling is for the game to go on.