It is not impossible to ban gambling. If the government wanted to ban gambling, they can ban it promptly. Even history can show you that gambling can be ban. Ancient Rome ban gambling, China ban gambling, and many other government especially those with Muslim religions ban gambling. Gambling can easily be ban but it cannot be stopped. People will find way to engage in gambling activity eve if it is illegal.
That's true. A total ban on gambling is not a viable option. It can be banned but the government cannot stop people who are really interested in gambling. They will find a way to gamble even if it is illegal. And they can't stop online gambling since the internet is so open to everyone. The only think I think is logical is the legalization of gambling in a controlled and regulated environment.
Finally, gambling is a wasting habit which is not good for our economic stability or social life. If there is no proper regulation and gambling bets are placed illegally, it will be abused and the negative impact on society can be severe.
The main reason governments don't ban gambling is the money it brings. Gambling houses earn a lot and they pay a lot of taxes. These places also require licenses that cost money and have to be renewed. If they do anything wrong they can be fined which is also money for the government. If they ban them all of that income is gone and people will still gamble in shady dens located in a basement where they'll be cheated and robbed every day.