And that is why it is called gambling, because of the risk involved and you will just based everything on pure luck. Even if let's say you are a professional player, still you don't know if you are going to win every night, hence it's not a way to bring income and food in the table for your family.
The uncertainty in the outcome of gaming session is always unpredictable and most time depend largely on luck since the casino will never allow the gambler to win easily over the house so that makes it to become hard for gamblers to time themselves and work toward winning at repeated level, but then also we talk about the possibility for the gambler to have been lucky to have won big amount once, by hitting the jackpot and saving some of that money or putting it into other a business that can help bring in steady income.
So gambling can bring in good income if only we can diversify the earning we generate from gambling and this is something most gamblers should have thought about, and try to work towards.