The success so far is really just political, which has largely been shutting down debate and dismissing calls for some kind of cost analysis of what we risk losing in enforcing this.

Whenever someone brings up this stuff, the politicians take the tone that "we won't let anyone get in the way of protecting children", and this is in response to people who in good faith think this can be done better. Media oligopolist love it because it regulates big tech, so they've been happy to platform supporters of the policy as well.

Third spaces won't reappear because the planning system in most cities shuts anything down the moment someone files a compliant. They get regulated out of existence the moment police express concern young people might gather there. The planning system (which in NSW/Sydney is the worse) has only gotten worse since the 80s after the green bans. It was largely put in place to allow for community say in how cities are shape, which sounds nice but it's mostly old people with free time participating who don't value 3rd spaces, even if they might end up liking them. They just want to keep things the same and avoid parking from getting overly complicated (and this is a stone throw away from train stations and the CBD).

Third places can be fixed by reforming planning which is slowly gaining momentum via YIMBY movements, but this social media ban is just not a serious contribution to changing that. If anything Social media phenomenon like Pokemon GO contributed more to these third places lighting up.

Governance in Australia is very paternalistic, it's a more high functioning version of the UK in that sense. I think it might be in part due to the voting system being a winner takes all single seat electorate preferential voting system which has a median voter bias for least controversial candidates.

As a kid I always felt being in Australia you missed out on a lot of things people got to do in America, that has slowly changed as media and technology has become less bound by borders but looks like that being undone.