You're making the blocking at isp level sound more effective than it is. It isn't 100%
Even with the intro of age verification we're seeing, this will be a long road as we deal with the issue of vpns, and as we find sites that aren't classified as porn, contain porn.
I'm referring to services like steam, xbox etc which are shockingly aimed mostly at children and regularly contain porn..of varying weirdness.
And no amount of 'family safety' settings will block, because filters seem only to hide images if the publisher of the photo marked it as 'adult'..which they don't always.
And removal of the photo takes someone to report the image.. So it's often visible for a good few weeks.
Then the uploader/publisher account is deactivated, and they create a new account to start again.
I've complained multiple times to Microsoft, but the long and short of it is that the parent should be watching their child at all times when on xbox.
OK, that's fine.. But don't lull parents into a false sense of security with parental controls that don't live up to their promises.
Sometimes I spend time reporting images, but it's futile.
Ebay is another culprit.
I'm not sure how it can be dealt with, other than introducing a system where website users can report porn images on sites that aren't age verified, and it fines the website host heavily enough for them to be more proactive about checking the content they host.
On the other side:
I admit that the definition of harmful content is always changing and there's definitely a censorship risk
E.g would discussion around the trans debate have needed you to verify your id via bank details?. And would that have meant a lot of people wouldn't have entered the discussion for fear of repercussions?
Perhaps the Tavistock stuff would never have reached the conclusion it did (that it harmed children) if it hadnt had the level of discussion it had because people felt safer to air their views in anonymity.
Data leaks seem commonplace too
Overall I do feel like kids accessing porn is harmful enough that anyone who's content is wrongly blocked behind a age verification wall should be ok with the ability to appeal the decision and get the restriction removed.
Perhaps receiving compensation for any losses.
Ultimately, if all methods of circumventing the new rules were cut off.. Then the removal of porn from society (perhaps dying out, because no one wants to verify) would be a good thing for both porn consumers and porn products.