You are actually true, no one will always win a gambling. Gambling can not be the main income of someone life, it should be just an additional income for someone
Practically gambling can be an additional source of income for no one. Because there is no consistent income or profit from gambling can be achieved. Even someone makes profit rarely in some days, they will lose more than that in some other day.
Actually things like Sports betting and Poker can work out for people. I have a friend who has been sports betting for the last 7 years and has been making a good steady income of 500-1000$ sometimes above monthly.