The biggest reason why the gambling is more successful business and it is always risk for the gamblers when the gamblers win the bets they will play for more to earn more but repeating the same winning is not possible for many times so they are going to lose more money than winning and the people who lost their bets keep trying again and again to recover from their loss so they also going to lose more money if they play more.
I guess its human nature that when they start to win, they will continue and will not stop until they feel they need to stop like when they don't have money anymore. Self discipline and self control should be practiced at all times. If I play in real world casino, I would bring someone with me to remind me when to stop. Online, I would set a limit on when I need to stop and access to my extra funds should not be within reach.