Healthy gamblers are the majority. I wonder if there's something we all have in common that keeps us on the right path and never oversteps our limits.
What differentiates a healthy gambler from an irresponsible gambler is greed. I would have said maybe because healthy gamblers have other sources of income that is why they don't invest so much in gambling, then it also occurred to me that even the rich and wealthy can be irresponsible gamblers and cause their own downfall from their reckless gambling style all because they want to double their money so badly.
When healthy gamblers go out to gamble, they bear in mind that winning is not a "must" in gambling, so they will accept every outcome the way it comes. Other gamblers will keep increasing their bets so they win that money by all means.
Based on what you've said, I conclude that this happens because there's a lack of discipline in gambling, and the mindset of wanting to double your money is clearly the primary goal of many people addicted to gambling. Even those who are wealthy don't necessarily have the mindset of wanting to earn large sums of money simply by sitting back and enjoying themselves. There are rich people who have fallen into poverty because of gambling. I agree with you about healthy gamblers; they can accept whatever the outcome, but this isn't the case for those who are truly addicted, as they are likely to return to gambling, perhaps even more aggressively.