I never think that one can win in gambling if he can analyze thoroughly in gambling. Moreover, no matter how experienced he is, he cannot make any certain prediction about victory. And if in such a situation a person cannot take one as a full time job anyway. He may be ahead in gambling due to good analysis or experience in gambling but depending on it there is no chance to ever consider it as the main source of income. Although there are people in gambling who are professional gamblers but they have sufficient means of other income besides gambling. I don't think it is possible to lead life depending on this uncertain income.
Gambling isn't the same as trading or investing. Even if we learn it seriously and do deep analysis, no chance to ensure the win in gambling. Moreover, when we play luck-based gambling games. The only factor that can determine whether we win or lose, is our luck. Sure, it is impossible to get certain income from gambling that we expect from winning the games.
You're right, that matter makes no chance for hoping the full-time job in gambling. We must get a job that can earn stable income, we need to fulfill our daily, weekly, or monthly necessities. If we rely on the gambling, surely we can't fulfill the necessities because we don't know when we will win the prizes. As far as I know, people even mostly got losses in gambling.