They believe that they make it through gambling that they can be rich with it some day, i will also say it is laziness they feel too weak to work which they have working as long process to make money. I have a friend who is like that he never want to work any money given to him is specifically for gambling he also believe to win millions in gambling he has tried it for years and nothing is working and as a young guy age is longer with him of recent he has killed the believe of getting rich by gambling he has now found a work for himself which is getting busy now he is still gambling but not as it was before.
We shouldn't take gambling as our source of income.
That's right. because if someone actually has a job or a kind of work that engages him, he'll have very little time to spemd gambling and when that happens, it becomes difficult to get addicted since they are actually not relying on gambling for a source of livelihood, which is actually the fasted way for gamblers to feel entitled, raise their expectations and by so, get addicted easily just like your friend who depends on gambling for survival.