Then it is also as much as the other way around, every one's win is another's loss in gambling.
Career does not mean everything has to come from the player. Maybe someone has a career as a gambler because of the frequency of his wins, from that he becomes a gambling figure and works with several gambling companies as part of a team such as influencers, testers, or others. It was a career in the gambling industry.
But in general, gambling is not part of a career because it causes more problems than profits
All kinds of careers also rely on luck for profit, let's say an actor.