It may sound weird but I am making good amount of money from gambling as I find it the most easiest way to earn bitcoins in quick time and I am sure most of the people will find it risky way to earn bitcoins but I am very much comfortable in earning with gambling.
I have seen many people who are earning a living from gambling so I think even you are one of them who is able to make regular money from it as gambling is not a cup of tea of everyone and most of the people will prefer to gamble only for fun.
You might be right that some people are able to live from gambling, and they are constantly doing this however you may not know, that they dont do any kind of gambling like dice,slots or anything like that.
To earn a living with gambling, you need to focus on such games as poker and blackjack. If you play those, you may have a chance to overcome the house edge by doing correct decisions: but it is very hard to be succesful in such a games and play at tournaments where you can earn a big jackpot from the reward given to the winning player.
I think that gambling should be never considered as a way to make profit, unless you are doing one of these games. In other scenario, that should be just plain fun.