The government can ban gambling if gambling turn from social lifestyle to something people can't get their life over. Just imagine that today, everyone that gambles lose money in gambling and yet they are stuck with addiction, they can't get out and it seems like a cult that is very hard for people, the government can ban it because it looks like a harm.
Aside from that, the government can also ban some casinos under the regulations of gambling and regulatory board, it's something they can do because they have the power to do so. Also, in a country where there is dictatorship, their government can ban it.
The Govemment can not wake up and ban gambling just because few idiots are addicted and staking more than they can afford to lose, they can only impose some strictly taxes/rules to reduce the rate of active gambling activities. It's written everywhere and the gambling industry are creating awareness to only stake responsibly, dint come to their platform and start playing like your life depends on it. Gambling is for fun.
Just because some idiots are getting ruined doesn't mean some other people are not making a living out of it..
Yes you are right, gambling is a game of luck and there are people who are very lucky about the game while other aren't that favorable to gamble. Those who are lose won't used because they are losing and ban gambling but as you said, there could be stricter measures to implements towards gambling.
As we know, people are also making living from it and they are entirely losing and even though they lose it's not completely empty and of course those who are becoming extremely wealthy through gambling are making it in life.