People with infinite money who were gamblers or addictive gamblers, most probably wont drop gambling completely, but will gamble less, that for sure. Their goals what they want from gambling will no longer be achievable. They wont gamble for money because they already have infinite amount. They wont gamble for fun, because with infinite amount of money a million new ways to get fun opens
Yes, the question is what they expect from gambling. Maybe even if they have an infinite amount of money, they can still continue playing for money. Because they're interested in the very fact of their victory, and it consists in multiplying money. If they're interested in the fun aspect, then despite all the available ways of getting such an experience, they can still return to gambling as a specific type of enjoyable activity in their understanding, because it creates the excitement they need.