According to estimates and statistics of bookmakers less than 1% of players in general are successful.
That's pretty low, maybe this is true because gambling is a game of luck and we know that house always win and they are the one who make a lot of big profit. Lucky to those 1% population of gamblers, they must have a better life now. I never met a successful gambler, they are hiding from me because they know I will ask for some money. 
I am yet to meet any person which fall in that 1% category of wining from gambling. Maybe those who win in gambling hide themselves or does not want to be disclosed. Anyways it is also one fact that No. of successful gamblers are very less as compared to unsuccessful gamblers.
I too have a same friend who won huge amount of money from gambling but keep betting all the rewards amount on the next bets he lost all the amount in less than a month.