Maybe it needs a system where the account locks if there isn't occasional parental monitoring. Then the kids would be the ones encouraging their parents to check. Maybe the parent has to take a selfie for facial verification or something.
People naturally would ask "where are his parents?" ...she's a single mom working two jobs, and he's at home with a teenage sister as his only supervision most of the time.
This isn't uncommon in the US. I was a latchkey kid myself, my babysitter was TV. People say that parents need to pay attention to their kids more, but parents don't need more or better software, they need money and time.
The subset of people I'm talking about almost certainly don't fit into this category. There are still millions of kids with struggling parents who don't have proper guidance (note, guidance isn't necessarily supervision).
In the case of parents who are spending more time than ever with their kids, the problem could certainly be more related to aptitude. We live in a society where our lawmakers don't fully understand the technology most people are spending hours a day being manipulated by, so it certainly seems likely most parents don't understand the impact either.
Either way, to say that these companies will solve it themselves with better software for parents doesn't seem like a solution to either issue. It's kind of like "the factories are safer for children now because they're wearing hard hats" — it's the wrong conversation driven by the wrong people.
Those selfies for facial verification would most likely be used for something unrelated and most people would be unhappy with if they knew. Think of the ways these could be misused.