If you have been gambling for long, I mean for a veteran gambler no amount of winning streaks could get into his head because he has seen and had many experiences with the act. He just accepts the winning streaks as they come in, knowing well that after a win comes some losses too. Gamblers that are mostly carried away are the newbie gamblers who haven't undergone through some of these experiences, as a result they get easily carried away.
I got your point, you are saying the truth, there's no way winning from gambling will get into an OG in the system but we should also get it straight that it will also depend on the amount the old gambler won, as an old gambler let's say you have been winning big, May the amount you have been winning is small and you eventually win something very big, the excitement might be much but wouldn't get to the level when newbie gets such winning, I think I miss out something, some old folks in gambling still react as newcomers, there action will even get wondering if they are actaully what you think they are, so it seems this is an individual differences not actually all old gamblers can withand such to pipe low.
Those old gamblers who stay calm after big wins are usually the ones who have lost a lot in the past, so such a win doesn't mean much to them. Of course, there are also those who celebrate as if it's their first time winning. But when we look at the situation, the gamblers who stay calm after big wins tend to win more often.