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.
luck should not need to be discussed further because after all it is a basic thing that must exist considering that gambling will certainly not be separated from the name of luck in the connotation where luck always takes a bigger role.
But besides this, of course there are several other factors that we must have because not all gambling is only based on full luck such as poker that you mentioned or even betting on sportsbetting where not only luck plays a role but several other things including discipline and mindset are still a reference.
Indeed, in the end everything will not be separated from the name of luck but in the current context when talking about gambling in fact it is not as simple as where we only rely on luck and courage because for some games as we have discussed as an example of course it also requires other things as a reinforcement of our probability of winning.