Online or not, gambling can only be limited based on individual decisions and those of the casino, but it can't be entirely stopped. It's always easy to start something, but stopping it is always very hard to do. This is not just something with gambling; it's the same in every aspect of life.
Online casinos can't be stopped, not even with government intervention. Most of these online casinos don't even need regulation to function; what they just need are active customers who are ready to start their business. So how can the government give others the power to stop something that is not under their watch? And even if they give a permanent ban warrant to their citizens, what happens to VPN? People will still use VPNs to access online gambling sites and make sure their pleasure is satisfied.
Okay, let's also assume that the government succeeds in limiting users access to casinos. What will they do with physical gamblers? Let's not forget the fact that before the online casino started, gambling was already far from existing, which is where the idea of taking everything digital and making it less violent comes in, so if you are talking about stopping online casinos, we should also consider where it comes from.