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.
Isn't it obvious that you can't make a "regular" income thru gambling? Because for me that is the definition of source of income. That you have a regular job that you got paid bi-weekly and monthly. And with gambling, it's very hard to do that or it's impossible. Sure you might win one time, but it's hard to do that again and again and duplicate it. So there is no doubt that gambling can't be a source of income.
Unless you are a gambling operator, casino itself, or running a illegal den in your country wherein it can rake a lot of money. Or one time, you really hit big by winning the lottery and it did chance your life for the better.
It's a source of entertainment not income and can't be rely on but for gambling shop owners and casino owners, are the ones making money from gambling.
Nowadays most jobless persons has turned gambling from fun to source of income in other to make livelihood from it, but yet it still remains what it is because you cannot change the nature of gambling from how it has being from ages, but rather endangering their lives and present financial condition.