When you are playing a game that is based on pure luck, you will going to still lose even if you do martingale. This is because the casinos have already setup that at the end of the day they are going to win because of the house edge advantage.
House edge is not technically an "advantage". It is the edge that the casino has due to the design of the game of chance over the player. In other words in every EV- game the odds are against the player and so even if they do whatever mind-boggling strategy they will lose at one point be it short term or long term. The casino does not have any "advantage" over its players. That would be cheating.Quote
However, if you win big and cashout, then you are really lucky but the house will still be able to recover from other bets of other players.
Most big winners actually end up losing the amount they won because of greed. 