Well it exists in Privacy Pass, which is deployed in production. And there are countries that are currently actively looking into privacy-preserving age verification. I don't think that "I keep saying that age verification fundamentally leaks your ID, which is wrong, but it's still valid because nobody will notice" is a good argument.

> The only privacy-preserving (effective) age verification is asking user if they are over 18 and requiring that they answer truthfully under penalty of perjury.

I disagree, I think that there could be a sane debate around ZK age verification, if we could elevate it to that.