Do you think that with taxes imposed on individual gamblers when they win will limit gamblers from continuing gambling? I don't think so. This is an attempt by the government to get more taxes. They may intend to discourage their citizens from continuing gambling, but with the large tax contributions from gambling, they may not want to lose one of the country's sources of income. That's what happens to gamblers, getting a win is already difficult, but when they get it, gamblers still have to share the fun with the government.
The government sees gamblers as pit bosses, they know very well there is no way gamblers resign if taxes are increased instead it fills state coffers. You know Gambling taxes increase every year and the cash flows in. But does it control our habits? Not really, regular gamblers just keep playing any way. Think of offline bans, countries like Cambodia / Turkey ban gambling, yet people still bet through illegal channels. This tells you, taxation or outlawing will not stop gamblers any way, it just pushes them into the shadows.
A smart play? Legalize gambling under strict rules, catch it, regulate it, tax it and use that revenue to fund addiction support and regulation. I'v seen an EU report where it proved online gambling taxes have not driven gamblers away from legal website, but rather have destroyed efforts to reduce harm by pushing them overseas gambling website. So yes, governments should tax gambling I'm not against it, but only within a regulated & responsible framework. Outright ban or higher tax increases, this only empowers the black market, and it is a losing bet for everyone.