They'll just get it somewhere else, private chatrooms, torrents, etc and from probably even less regulated and more nefarious sources that also serve stuff super hardcore or completely illegal.
As an under 12y old, my first encounter with porn was as porn paper magazines rolled and stored between the wall and the radiators of my school class. No amount of server side age verification will prevent kids and teenagers from sharing stuff.
As a parent I'd rather pay for access to an ethical porn website that promote pleasure for all parties and safe sex and give access to it to my teenagers than trying at all cost to prevent them from seeing all porn.
And age verification can't stop that no matter what. It's solely for restricting access to websites and apps.
> No amount of server side age verification will prevent kids and teenagers from sharing stuff.
Great, now convince the politicians and the voting public of that. See how things are going. It would be better to have some system in place that protects adults' privacy and restricts some underage access. Instead of having to upload your passport to every website 5 years from now.