In my opinion, winning in gambling is not only about profit but also discipline. When we can stop gambling at the right time, that is also a victory, even if the gambling ends in defeat.
Partly, it's not just discipline, but also luck. i repeat it endlessly: professional poker players are good, they're disciplined, and they have a mega-brain that can calculate the odds quickly and for hours at a time.
But if luck turns against them and they receive lousy cards, they are destined to lose anyway.