The government isn't helping you, they just pushed every child in Australia to un-moderated and decentralised social networks. Complete free for alls.
4chan, Mastedon, BlueSky, PeerTube, Pixelfed
They have millions of users. They're about to get more.
No, you can't block these. No, you can't order these to do anything.
As others have mentioned it's the critical mass and the algorithmically-addicting dopamine treadmills that are the problem this law seeks to address.
What social networks are these? If they aren't complying with the law, they can (and should be) blocked.
You're also missing what folks keep saying: the network effect isn't there. It needs to be popular enough that there's social pressure to be there. If it's that large, it's going to be large enough to be on the radar and then be under enforcement.
Slippery-slope arguments, for the most part, exist to fear monger folks away from change, even when the argument itself is non-sensical.
This idea that regulation fails to destroy industries is farcical. Most examples of “failed regulation” like American prohibition were runaway successes as public policy. Whether it is good or desirable is a different question.
The idea that someone is going to make an engaging experience on a “decentralized” network is honestly a bit silly to me. The market potential of this business is low. Decentralized networks with much larger incentives have failed to capture critical mass.
There will be side effects, but social media has been so ridiculously corrosive to the welfare of teenagers that I can’t imagine a ban would be worse.