You can’t pass laws that require sites to block access to everyone under 18 without also requiring them to thus be able to know the ages and thus track the identity of all their users. Even if they outsource this to some ID verification service, that service is now tracking people’s real identity and sites they visit.

Some states are already requiring this for porn sites and social media sites. No doubt it will spread to dating sites, messaging apps, etc to “protect kids”https://www.theverge.com/2023/8/4/23819578/kosa-kids-online-safety-act-privacy-danger