Probably a small number of people can boast of being able to walk away from a casino with winning, and there are many more stories of failure. Risking your last remaining money is not a smart thing to do. I don't think such people have any strategy or plan of action for sure. It's just a huge success that happens very rarely, maybe even once in a lifetime.
True, it doesn't usually happen. It is totally on luck. However, it is not unusual to win small amounts of money here. As happened to Smith. But he gambled with $5,000 for about a week and won $17,000. This amount is not very high in gambling where many people have records of winning millions of dollars with keeping very few dollars.
Not everyone could boast about their winnings because, to be honest, most of us walk away from gambling because we don't have any capital to use since we've already lost everything we had. There will only be a few people who can succeed and reach their target goals in gambling because, to be honest, gambling is a game of luck and it is not strategic.