Gambling is only a game and there is no 100% that you can win here so this is not a good idea to make it as your way or your source of income. I dont think if there is someone who gamble that consider it as source of income because it is just a game with no assurance of winning or earning money.

The only person who can make it as source of income is the owner of that gambling, they are really the ones who are making money and getting richer because of the gambler.

Do not spend all of your time in gambling, it will just make you addicted.