I find it difficult to understand what you are saying due to grammatical errors but I assume you are saying that you overheard a person saying: if online gambling ceases to exist, then this will cause financial and economic ruin?
First, I doubt that this will happen due to the benefits that online gambling brings to the government. It provides an additional revenue stream on the part of the government due to the taxes being paid.
Second, even if they remove online gambling, there are still other ways in order for the government to generate income. Sure, it may hurt the economy but there will be ways in order to compensate for it.
Lastly, if online gambling is removed, then people would go back and switch to the traditional physical casinos though expect a significant drop in numbers.
Again like what I have mentioned above, there will be other ways in order to generate revenue on the part of the government.
On the side of its users, people would switch to physical casinos. But if you remove gambling completely, then I guess people would find ways to exhaust this kind of addiction into other ways.