An adult had to pay for the ISP connection; that's the extent of age verification needed. We shouldn't be demanding adults expose their identities to for-profit entities and surveillance states, so much as mandating for-profit companies make parental controls easier to use, more effective, and stopping them from harvesting data on kids in the first place.
Not every corner of the universe needs to be baby-proofed; we just need to build a society where parents are enabled and supported to be parents, rather than outsourcing such a critical role to strangers and/or devices so they can get back to work.