[Shorn]

Don't forget non-commercial stuff is happening in this area too.

For example: https://orcid.org/

Anyone who wants one can have their own Orcid Id in two minutes flat (and they're the only major SSO implementation i know that actually let's you keep your email private, other than Apple, i guess).

They support Oauth/OIDC, and you can even allow people to sign in to your own (non-commercial) service with their orcid via OIDC - it's no harder to setup the integration than Google or Facebook.