Offline and online are not equivalent spaces. They're not symmetric, they don't fail in the same way, and they don't have the same hazards or risks. I say this because I don't think the argument that we should do it online because we do it offline is coherent.

I actually don't have to show my ID when I buy alcohol because I'm old. There's a material difference between an electronic record being submitted, passed through and stored on several different servers, and somebody seeing you and seeing a grey beard and saying, yeah, you can buy that beer. The worst case scenario in real life is that the bouncer at the bar looks at your ID, seems real enough, checks the date, matches the picture, and that's it. There is no record being stored, there is no log. It's not equivalent to the vast majority of online age verification mechanisms in use today.