There's a reason why they gamble, they still want to win big as that's the ultimate purpose of gambling. No one in this world had an infinite amount of money even if we call them to reach, they still get excited and want to win, so in the process, they get addicted as they also have an ego especially if they are losing. Them not being able to control their emotion, that will lead them to bigger problems and that could result in bankruptcy.
and everything you say is connected with fate, that gambler is destined to be lucky and win in a few rounds but because he is greedy then his fate changes and he loses in the next round....fate, luck, and misfortune are like a unit that can't be separated, just how can we take advantage of our luck when it comes when we gamble.