Gambling can be profitable in REAL casinos using professional methods of card counting and bankroll management combined. Just search the MIT Blackjack Team as one example. Online Casinos you will not be profitable in the long run unless you hit a jackpot, or are a sports bettor that has the skills of a professional handicapper.
I'm not sure can be profitable in the longterm in casino gambling and I do not think any methods in gambling because it is depend on luck.
In a casino where there is a house edge for short your cannot win in the long term because it was designed only for entertainment for the gamblers and the profit for the operators, we cannot argue on that because it is the reality that we need to accept.