I see profit all the time in gambling.
I know many people who are ahead in tens of btc and started out with little.
So it is possible it just seems very slim when sites have thousands of users complaining they only lose.
Im talking about gamblers..
Here is a site with a list of the top 300 tournament poker players this year: http://www.pokernews.com/global-poker-index/
The list is updated weekly. This is just a fraction of the tournament poker players AND tournament poker players are, yet again, only a fraction of the pool of poker players. Cash games are more lucrative, more common, and more accessible.
It's not easy. You have to treat it as a business and put in a lot of work for it to be profitable. Here's an article by one of the best that explains the thinking required to become a professional poker player: http://www.cardplayer.com/poker-blogs/2-daniel-negreanu/entries/562062-a-foolproof-plan-to-becoming-a-professional-poker-player
Just search david choe he is a gambler.