More than 50% of the world population gamble in one sport or the other and some are making good money while some are still hoping and praying for their luck to shine.
Gambling CAN BE a source of income, but just a side hustle. you cant make it as your primary source as you will hit below zero and that is for sure.
As for me now, i do earn from online casinos, using the forum and it is a good amount to earn. joining also their contest is good.
Another way to earn from gambling is to advertise them or be an vlogger/influencer and get paid by them.