It’s not a solved problem at all. Your take is very libertarian, which I personally sympathize with, but if we’re being honest it doesn’t align with reality.

The truth is, there are a lot of bad parents that are, for various reasons, unable to perform these parental duties.

We’ve always restricted children from accessing certain things without relying solely on their parent’s abilities or discretion.

I’m strongly in favour in giving parents as much control as possible. That doesn’t negate the fact that the vast majority of children, for example, currently have completely unrestricted access to hardcore pornography.

Shrugging it off, proclaiming it’s a parental responsibility, doesn’t solve the real world problem.

Previous to the internet we didn’t allow free unrestricted distribution of pornography to children. We stepped in as a society and said, no actually if you’re selling that… fine, but you need to verify the age of the customer.