the answer is always simple, do other mediums.
You are right, the answer is quite simple and clear enough. We all know there are many other alternatives, and I think the most appropriate alternative is playing online gambling. The activity will be the same, the games seem relatively the same. So, the addicts will still enjoy gambling games almost like they play in physical gambling places.
It is true, there are so many alternatives that they can do but the most efficient way for them is to play online gambling. Though it might be different from the vibe they feel when they are inside the gambling house but the activity is indeed the same.