You are right but such a scenario is very uncommon, after all at that point greed takes over those people as they think that if such results can be maintained during the long term then they could make gambling their main occupation, so they gamble again thinking they will get the same results only for things to change and experiment some heavy losses, then instead of simply accepting that their results have gone back to the mean they gamble even more money, and that is how they end up returning all of the money they won to the casinos.
This is the most common mistake when, after a long series of failures, the player tries to increase the amount of the bet and thereby hopes to win back the loss. But this only means that the player turns on emotions, and it is clear that in this case the loss is inevitable and it will be a more significant loss. Even if this time the player is lucky and wins, it will be even worse because he will think that he can win back in this way, and as a result, he will return to this method again and again until he loses all the money.
One hidden truth about gambling is that the more you attempted to win the more you're loosing because one cannot approach gambling with being too emotional and desperate for winning alone when it's a likely possibility for either winning or loosing, this is part if the risk involved that you find out some matured gamblers don't go after winning but the fun the derive in gambling is their major priority which that's how it should be.