ID will be a new form of auth. ISO-18013-7 establishes the equivalent of OAuth for electronic ID presentation on the Internet. It's already accepted. Apple and Google announcing the ability to use your ID at TSA is ISO-18013-5 and it's a short hop to 18013-7 from there.

We will be barred from accessing sites without valid ID. The question is can we get a few IdPs to provide the ID in a privacy sensitive way (the relying party really only needs to know your age after all).

Ideally an international governing body, under the auspices of the UN, holds the IDs and transmits the specific claims when requested and keeps no logs on requests.

Realistically it will be Apple and Google and you'll just have to trust them to totally not use the data of what sites request your ID to track you (lmao. lol, even.)