The player has some funds to win through gambling. Unless the casino has no provably fair feature or operates a 100% house edge, the gambler has some percent to win in every $100 they wager in a casino. Depending on how well they try to wager the money. Not talking about a player who wagers his money at once. Those who want to target the reward per $1000 wager, can be staking $50 - $100. Players looking at $100 can focus on wagering smaller amounts like $5 or $10 to enjoy their game till it gets to that threshold. However, it is not made to look this way in the casino, but the house knows a way of rewarding players, to keep them in the casino, thereby making more money for the house. If a gambler doesn't win at all, he won't be energized or motivated to gamble again. So, a gambler who's determined to take gambling as a career must know the house edge and the provably fair of the casino they want to make their office.
It's encouraged that the gambler starts up with a good amount of money and wagers accordingly to extend his days of gambling and increase his possibility of not running out of money. Given time he'll be earning some money to add up his existing bankroll. Thereby enjoying extra days of gambling. If he's well calculative he won't run out of money. But, the player needs to have spent years mastering the act of gambling, to consider gambling a retirement plan or a form of career for the long term. He may not expect to earn more profit, the gambler will not be in profit but can maintain his money not to finish. Moreover, if a gambler is not organized or has the skill to manage his money or be carried away to lose control of his plans, he should venture into such a risky game as a business. But the possibility is there to make a career in gambling.
Even though gamblers have the opportunity to win from a certain percentage of the money used to gamble, they still have the opportunity to lose or even lose all their money. This is what gamblers must realize, especially since they already know that they cannot possibly beat the house because the house is the business owner. Gamblers can only choose the bet amount they can afford and then enjoy gambling, and if they win, they should not continue gambling again in pursuit of bigger wins. A gambler who doesn't win will become curious about why he can't win and try gambling again another day. It has happened to many people, even those who want to make gambling their career will experience losing even more money.
If gamblers don't realize that gambling is not a career, they will only encounter failure, and even if they keep trying hard, they will not succeed. That is why if there are people who still want to make gambling their career, they should think about the risks and what will happen to them. If they were wise, they would not make gambling a career but would only make gambling a part of their entertainment. They would prefer to enjoy gambling as entertainment because they do not have to lose more money, and also they can stop whenever they want. He can also manage his money well and will not spend a lot of money just to gamble because that is not his goal in gambling.
I think the main goal of such people is maintaining the money not to finish. Because winning big will only make such a player vulnerable to losing more money in gambling. These types of gamblers are currently not beginners, they've been running the process of learning gambling for a long period. Hence being able to manage the money set aside for gambling wouldn't be a problem for the gambler, due to the experience he has garnered in his years of participating in gambling. Gamblers who face the fault only need to make money and don't have any experience or research available to help them achieve the goal of gambling as a career. We all understand how difficult it is to gamble, not to talk of gambling as a career. Somehow the person playing as a career with his skills would earn the money left for him by the casino. His percentage, because he gambles cautiously, would be given to him as a reward.
Since the house has made it that way, it's not something to be bothered about, whether the gambler would earn it or not. The mistake some gamblers make is that they want to get the reward immediately, as you said. Sometimes it takes weeks to gain the money, and when such people, inexperienced players, see the reward they hardly control it, instead the money leads them to gamble more. While those who are experienced enough to handle gambling as a career, may see losses, it still requires their management skills to know when to stop for the day. However, this type of career is not meant for most gamblers. Because they won't be able to withstand the problem gambling that might face them in the process. That's why I do recommend, that players with skills and gambling experience venture into such a career. Moreover, the player must have lots of money to finance the gambling lifestyle.