Remember that when discussing any regulation.
The „it’s impossible” and „let’s not bother” people are a scourge and they mustn’t be taken seriously.
Instead of large, accountable providers, now three quarters of their customers use vpns or switched to sites without age verification.
Yes, and we were right.
It was billed as something that most adults would accept. It's not plausible that 77 percent of Pornhub's UK traffic came from non-adults.
It has therefore failed. Obviously a huge number of adults did not accept it, and either went around it or stopped using the site. What they did not do was to comply with the supposedly "measured, reasonable and non-intrusive" AV measures. They accepted costs and inconveniences to avoid that.
It was billed as something that would only affect children. It has in fact affected many adults. That means it has failed.
Of course, many of the 77 percent have probably moved to VPNs (or other sites) rather than actually not using Pornhub... which means they were only inconvenienced, not deprived of porn or even of Pornhub.
But those approaches are just as available to non-adults as to adults. Although the AV nonsense probably did actually deter some number of underage users, you can't know what that number was. It would be possible for literally every single underage user to have simply switched to a VPN. The 77 percent number tells you exactly nothing about how many children have been deterred from watching porn. Probably not very many.
So although this does give you proof of some of the ways it's failed, it does not give you any evidence that it's succeeded in anything at all.
That said, that kind of "success" is not the main issue. The main arguments against this AV stupidity were and are that it's not worth the huge costs in money, convenience, security, and privacy, and that it helps create machinery that can and probably will be abused for other purposes later. All of which are still absolutely true.
It's also much more obvious that a taboo/illicit service asking you to, essentially, deanonymize yourself is going to be hit the hardest.