Yes, and that thing is chiefly corporate social media. Which could be fixed literally overnight by parents, over a few weeks by school district policy, and over a few months with sites publishing metadata to aid client side blocking. Phones, the primary independent computing device for kids, are already locked down to the point that an owner has to jump through many (detectable and auditable) hoops to install arbitrary software.

None of this requires some draconian regime where it becomes sites' own responsibilities to obtain and verify their users meatspace identities.