[throwaway41597]

The lock-in is very real and relevant.

Websites already have a hard time to get users to sign up, so requiring them to enroll backup authenticators (which they won't have) is not going to work. Printing or writing down backup codes is even worse from a UX point of view.

IIRC the spec has a flag to hint that the passkey is backed up (in iCloud or your Google account) so the relying party (website) knows whether backups are mandatory but that means the secret doesn't stay on your device and goes to the mothership. Then I don't see why the spec wouldn't standardize the transfer of secrets from one company to the other.

[skybrian]

That's a good point, but on the other hand, this "lock in" doesn't seem worse from how Chrome generates and saves passwords now?

It would be ideal to set up backup auth before you need it, but you could also do it when you decide to move off Google.

So, not really a lock. It's a vulnerability, though, if you lose access to the Google account for some reason.

[throwaway41597]

Chrome allows you to export saved password in CSV (chrome://settings/passwords) So I'd say it is a regression in this regard. You won't be able to switch to an other browser easily, you'll have to go to each websites and change/add authentication methods as far as I know.