The dopamine they have or they get every time they play gambling is the one who keeps them away on getting professional help or confessing to someone that they need help regarding about their situation in gambling being addicted on it. So the outcome of most gambling addict stories always end up in the worst case scenario, like they lost everything on them before they even realized that they should stop.
I think he might be right, but it looks like you misunderstood him. He was talking about gambling addicts, not all the gamblers. You are right that many (I would even say "most") gamblers start seeking professional help before it's too late. But there is a part, less than 5%, who are gambling addicts or problem gamblers, and it is very likely that most of them end up badly. It's not that they can't be helped, I personally know a guy who was completely cured from severe gambling addiction, but it's rare.