To be fair current age verification is useless. We all know clicking a button does not verify anything.
Also we know that submitting personal data to a website to verify your age is terrible. Big no no.
I'm curious of what will happen in my country. Here in Spain government said that they will implement a new age verification system using Anonymous digital certificates. The government will issue those and you have to give your ID but the certificate itself it's anonymous and the website won't be able to know who is the person behind the certificate. While there's no implementation yet, I hope they use the kind of anonymous certificates that, once expedited, the government also does not know who is using the certificate when serving as a certificate authority to validate its authenticity.
Let's see how it goes. I'm afraid even while being privacy friendly with this system Pornhub will block access here to as a threat to other places. At the end is a private company and blocking minors from accessing their content cost them big money, and, of course, money is the only thing that matters to them.
And what happens if the government needs that money and Bitcoin price is down?
I don't see how putting national reserves on such an inestable "asset" would be a good idea.