Based on the example that OG has given in respect to those that won huge jackpots, I think they succeeded in beating the casino but if they don't go back to spend the money on the casino, that's when they truly beat the casino but if they spend the money in gambling again, that's meaningless. Winning jackpots doesn't happen regularly, if a gambler is luck to win a jackpot and it surpasses all the money he has spent in gambling, that's when we can say the person has beat the casino.
You are right beaten the Casino is not only about winning a jackpot because the moment the person refused to make sure that the money they won from the Casino is used for a better thing outside of gambling then they have not beaten the casino, actually what Casinos believe is that even if you won $200k or million from them so long as the persons greed brought them back to the casino and they got all the money exhausted they have not beaten them but however anybody that say that no one can beat the casino is wrong because people have made millions of dollars with just a minor $2k they started with and use those money for business instead of regambling.