You can win from gambling from long run.Because of the house Edge you will lose if you gamble in the long run.If you gamble through poker or player vs player game you have high chance to win.But if you gamble vs house you will surely lose if you gamble long run.Read more about house edge.
That is most gambling method works and has a very high house edge, that is why many gamblers prefer betting in sports betting, poker, or a PVP gambling that they can analyze and put some effort of strategy and skill in winning, well you should think first because proceeding more further in that kind of method.
Just a small observation in sports betting you are still betting against the house unless you are betting in a betting exchange like betfair in which you are betting against other players.