I think rationally all of that happened because of excessive expectations of big wins that were initially based on a wrong understanding of how gambling really is, in any case misunderstandings can very likely trigger wrong actions that will lead us to something we don't want. And of course when someone has a high level of expectation then they will not care too much about their financial condition, they even dare to risk the last amount of money they have instead of using it for something more important.
Another thing related to the people you said who feel that they will continue to win are basically those who do not have a true understanding of gambling and how luck works so they continue to bet and feel that a much bigger win is near. That's why I would say that understanding is one of the keys to avoiding various impulsive actions, there is no connection between previous results and subsequent results especially when you bet on casino games, in the end and until whenever gambling will always be about luck as you said.
I would also say that risk awareness should be prioritized and maintained rather than focusing too much on winning, because it is a fact that the percentage of losses is much higher than wins.
Also people who don't know how to maximize the use of their luck, I mean if you got that chance to win and multiply your bankrol it's best to call for the day instead of pushing forward, those who thinks that they will continue to win more will eventually lose everything back and that's the common behavior where addiction begins.
Always have that good grasp of understanding to prevent making that same mistake, losing is something quite usual but also, winning can be a part of it if you know how to value and use your luck wisely.
What you said is true, making the decision to cash out early when we succeed in winning is a very wise action, this is none other than the perfect combination of prevention aspects so that we do not end up with regret and the following by helping ourselves to be able to enjoy the results of the victory, and this is also one of the reasons why I said that focusing on risk is much more important than continuing to think about victory, because by shifting focus completely to risk then you will prioritize various forms of action that lead to prevention, for example when you are in a winning situation.
I would say that making the decision to cash out early before everything ends in regret is a wise decision which indirectly is an action that is the same as you appreciating the luck that has come to you.