There is a possibility that your friend is rethinking about the winnings he got should not be given to you, because all the capital to bet on the match was entirely from his own money. What you said is right, people will never feel satisfied when they win a game from gambling, they will try again to bet on the next match without your knowledge rather than having to give it to you.
The cycle can only be broken by own effort. The casino thrives on you chasing your loss and if you realize this and accept the loss and make the decision to earn money from your work, save it and not play with it anymore, the casino will have lost its source of money.
That is actually how you can beat the casino but this is something most gamblers cant even think of because the "money making instrument" is right in front of them, why would they leave it at all?
This realization is the maturity that gamblers need to have.
I am sure many gamblers have the awareness and thoughts as you mentioned. However, not all gamblers can control themselves, especially when they are experiencing defeat. If we talk about leaving it altogether, I think it is very difficult because it has become a habit to seek entertainment or luck. Therefore, the right thing for gamblers is to limit themselves, whether in terms of time, money, or emotions, so that if that can be obtained, gamblers can become responsible gamblers, of course that keeps them on the safe path when gambling and of course avoids personal problems that may occur. We know that there are so many stories about problems that occur when a gambler does not limit himself.
Some one have said it before and I have also said it a few times that when has helped some people to be able to control their emotions or their gambling behavior is because they had a timetable they created for themselves and also some rules which they always observe those rules and discipline themselves to work according to their time table and that's why they are able to face their gambling lifestyle In a responsible manner. That's what everyone should adopt.