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.
I don't think that you have a verified statistics to prove what you said, neither do I but I seriously doubt that you are correct, I know that majority of the adults in the world don't gamble.
Anybody that takes gambling as a source of income will most likely become addicted to it because fact is that they have a higher chances of losing their money than winning. Gambling wins are by luck and it will be unreasonable for anybody to depend on it to take care of their financial responsibilities. Most people are not making profit in gambling, when they win they will continue to gamble and lose everything back to the casinos so it doesn't make any sense. The best mentality to gamble is to see it as fun, if you win take it but if you lose don't chase loses, move on them try another time.