I am someone who has always had the understanding that no one can live as a gambler, regardless of whether he is rich or not. Gambling cannot be used as a source of income, you can imagine how a person can live by gambling while he has to spend every day to live while he does not ensure that every time he gambles he gets money, psychologically this is something that can be accepted.
You've got a point .. basically, when someone is gambling they are taking risks for uncertain results in the hope of making a profit. So making gambling a source of livelihood is something that doesn't make sense because they have to depend on something uncertain.
But strangely there are people who take this path which in the end they will be faced with losses and after all the house always has an advantage because the odds are created to the house's benefit.
Do you know anyone who is taking gambling as a profession and yet making an household income for living ? I don't think anyone can make consistent income with gambling.
Gambling may give you a lot of money at once or you may lose all your money but getting regular income from gambling is impossible.