The reality is gambling is part of human society ever since humanity exists.
So the government can just contain it by legalizing its operations, and in so doing, get the tax from it.
Because if not, it will just continue to operate, just like you said via black market.
It may be resolving some problems created by the gambling itself, but we can't totally discard this industry.
We have to accept this industry and just look for the positive impact it can bring to the community.
Eradication of this is not possible. So one thing to do is to remind gamblers to gamble responsibly.
No! Turning a bind eye to the negative impact it has on society is stupid and generates countless of problems. What you said is literal equal to "we can't prevent people from drinking alcohol, so we just focus on the good stuff that alcohol does for the community". I say no! There are tons of treatment programs in terms of alcoholism and prevention thereof. The fact of the matter is that gambling as an excessive activity or even health issue is highly problematic and entails severe consequences for society as a whole. The difference between gambling and alcohol is that alcohol related issues can be calculated more easily in monetary terms. The consequences are very visible and people sometimes go into a hospital and demand treatment. Gambling, when people destroy their promising future, is much harder to detect and also to quantify. It's like the dopamine threshold for people to become happy is getting destroyed. Why can't the person who has to gamble to become happy and produce sufficient dopamine not just watch a movie in the cinema? It is because the kick isn't there. If the person does both, that's good, but if gambling turns into the only "hobby" someone has, that's already highly dangerous.