What's insane is that, in France, we have France Connect, which is exactly what you describe: a third-party authentication platform maintained by the government.

Lately, a new law just passed to force porn websites to check the age of visitors. I would have been fine with an authentication going through France Connect:

- the gov knows which website you went to, just like your DNS provider would, but it doesn't which content - and the website knows which content you've watched but not who's watching.

Best of both worlds!

But no, we have to send a copy of our ID card to the website, which is INSANE because the website knows WHO you are and WHAT you're watching.