Poker is the rare exception in gambling (for some of the players):
A small percentage of people who play poker can honestly say they make a large profit.
Around 5-10% make sizable profits after the rake, while up to 30% can say they are somewhat profitable. The rest are either struggling to get a hold of the psychological side of the game or are constant losers by default.
It can be said that any activity can bring a good profit. Ok, that's a possibility, but not mandatory. To me, this seems like an excuse for addicts, only in the end they were unlucky, one number or card was missing.
I'm pretty sure that there is an almost negligible percentage of those who have made a large profit from gambling. The exception is the house, which always wins.