I'm not sure those who are addicted will simply quit gambling. I think if they're addicted and run out of capital, they'll likely try to find money, most likely to gamble again Unless the addict realizes it and wants to recover from their addiction they won't be profitable for the casino anymore. However even then the casino won't suffer any losses because there's more than one person gambling. I think the casino still profits from people who gamble even if they aren't addicted.
Well, the casino structure is so set that, there will never be a situation where profits are not brought back to the organizers. You are right that in most cases, addicts come back even after losing all but more significant is the number of individuals who come to play just like burning their waste. I understand this as to why casinos do not actually deal with a loss as even the passive players are involved. Thus we can deduce that their earnings are secure not only through addiction, but also through the whole activity of gaming.