That can happen, and not only in gambling. I remember a story of a popular boxer who made a lot of money because he is good at what he does, and winning many fights. Years later, or when he is near retirement, he spends all his money on gambling, alcohol, and women. After he depleted all his money, he became poor again, living in the province and didn't even have a house of his own or any savings.
Anyway, you are right that a gambler can win millions and just switch to another addiction because he badly wants to spend his money on a luxury that he hadn't experienced before.
There was a time when I managed to win a decent amount of money in slots. Then I hit the daily jackpot and there was still money on the deposit. My happiness knew no bounds. What did I do? To please myself and stop gambling for a while, I went and bought household appliances for the family, bought a good mobile phone. Well, and a little more in small things. I am glad that I did not start playing again. I am sure that all this money would have been lost in a jiffy.