There was a time when porn could only be obtained by paying for it and guess what: kids still got their fix somehow. I sure did. There's always a friend/cousin that could get magazines and VHS tapes somehow and then it would made the rounds.
Oh sure. I remember the time when paper recycling boxes (or whatever they are called in English language) had at least one porn magazine out of ten boxes. One scouting mission would most certainly guarantee at least one magazine.
And very often an underwear catalog would do the trick. Just find the page where you can see nipples through the bra, or pubic hair showing through the panties.
There is still a difference in having a lifetime worth of porn - from the whole spectrum of fetishes, from everything between gentle and rough as fuck porn - behind a couple of clicks, than to scout a magazine here and there or to have a cousin loan you a VHS tape from his "huge" 30 tape collection. Or to secretly record an xxx movie from a pay channel your dad had paid.
It's like comparing mixtape trading to full blown p2p 24/7 music piracy. Sure at core both are the same, but surely they are way different at least in scale.
Locking down the internet would accomplish little: kids would just switch to sharing the stuff they got by using a VPN, pirate sites or from a older sibling through one of the many encrypted messaging apps available. Can't find porn? They can produce their own (which is becoming more and more common).
The only kids that wouldn't get it are the complete social shut ins, but those are likely to learn how to use a VPN on their own.
Well, at least the kids would have to be able to do that instead of having all readily available.
Anyways, this isn't about locking down the internet. It's just about having to prove your age. Then things would be available for those willing to see porn.
I don't quite get what people are afraid of. That it would somehow leak to others that you have proved your age to be able to watch porn? Or maybe it's a security issue because of having to give your credit card information? If so, how can they buy anything from the internet?