I live in Australia. The social media ban for under 16's was not successful at all. (this is anecdotal) Majority of social media platforms did not get effectively eradicated (including ticktock, instragram etc...) for under 16s. And at least snapchat (and maybe others) did get properly banned but then a few months later under 16s could log straight back on again with no issues.
Opinion time: even if the social media ban was regulated properly it still likely wouldn't be effective, sure children that abide by the law and aren't completely addicted will stop using social media. But the children that are properly addicted and need help are going to find ways around the ban, like using vpn's and get driven underground being less likely to seek help since there is now an extra reason for it to be considered shameful. Just like banning drugs, banning social media doesn't solve the issue.
I think an intelligent Marxist (not me) needs to do a proper class analysis on this I have found individual articles that have shown links between the social media ban and the gambling industry. And the gambling industry doesn't give a crap about weather or not the ban is successful they just want a public distraction from laws that prevent the gambling industry taking advantage of the working class.
I see that your Australian too, I am interested what information shows the social media ban to be successful, I could be wrong but I think it's safe to assume in most situations an apparent win for workers is disguised as a win for capital.