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.
Proof? Is there any proof that this is happening? Or it's just a random words coming through your mouth without any evidence whatsoever.
Gambling CAN be a good way or making money ONLY if you're lucky consecutively. The problem is, not all gamblers are experiencing that thing so in short, it can't be a STABLE source of income. It's very risky obviously if you rely your income on gambling, and I don't think there's anybody here that solely rely on gambling as their source of income. For sure those who are making money out of gambling has a Plan B just in case things go against them.
I always believe that gambling is a for of entertainment only, and not a way to make money. Sure, you can make money, but it isn't consistent enough for a gambler to consider it as a source of income.