I love how Tschai looked into both sides of the  answers to this question, but for me the answer can be quite tricky. I really do believe that gambling is a game of chance and luck, so with that you can easily state that it cannot be profitable in the long term since chance and luck doesn't really work with assurance. I don't know how gambling can give you assured profits every time you play since you don't know the outcome of the game until you're actually playing. On the other hand, as Tschai said anything is possible so I guess if you invest your winnings through different business or investment ventures then that's how, in some way, gambling can be profitable in the long run.