Better enforcement and better parenting are of course important parts of this but part of the problem is that the current laws were created at a time when we couldn't really imagine the smartphone and so are inadequate for the modern world.

There's also the problem of simply the viability of enforcement. Again we will go with the China example. Porn is banned there, you can just go through a VPN and get it anyway.

We can't enforce things that we can't see and a lot of this stuff happens in private so that the damage is already done long before anyone in a position of authority is even alerted to the issue. This is the same problem with parenting. Most parents cave and get their kids smart phones anyway and once you do that the kid is vulnerable and can easily hide whatever they want from you.

I think this is only going to get worse. The larger social ramifications exceeds the realm of simply good parenting. I think the least problematic solution at the current time is to put severe restrictions on minors usage of smartphones. Alternatively we could also put the onus of content delivery onto the websites themselves. But there would need to be real financial penalties and consequences for porn websites that allow children access and we can't allow them to claim ignorance lest kids do what you and I have always done and ticket the "Hell yeah I'm an adult" button when we wanna see tits.