It is pretty true. It is not a wise decision to make gambling be the main job because we can't expect to earn money constantly in gambling. Most gambling games are based on the luck, it is very difficult to always win in the games. Although we already played the games for many years, there will be always no guarantee to win them. Sure, experienced gambler must have better chances to win, but it doesn't mean guarantee the wins. Because of this uncertainty, it is better to gamble as a side activity. Or to make gambling just for fun activity. Don't try to rely for monthly income from gambling, it is a very high risky!
Maybe a gambling job that can be done because the profit is more certain is to be a casino owner or when we already have a win rate in sports betting it is quite good and open a tipster service, because the tipster will get money from the gamblers who use their services and usually the tipster will have two services which are free and paid and when gamblers are satisfied with the free ones there is a big chance of joining the paid ones because if gambling activities such as betting or playing casino games are turned into a job, it is very difficult to make a profit or target a profit that can be used for living expenses., because today we can win a lot but tomorrow it could be the opposite and because we can't control ourselves, it's not only yesterday's profits that run out but also our capital.