Your passkeys aren't synced to anything, so the passkey is no different than your password hash. They're device locked unless you use something like bitwarden, so you're no more dependent on American mega corps than you are right this second.

I'm wrong.

Say you don't understand passkeys without saying you don't understand them...

A passkey uses public key cryptography to secure your account instead of a password, it only grants you access to the one account you set it up for, and the account provider only holds your public key, you control the private key. Your passkey is a secure alternative to passwords because you CANNOT reuse it across services, cannot reasonably remember it, and the method of using it isn't by copying and pasting into a field like a password, so it isn't susceptible to the same attacks.

If the provider loses your public key, they can't give you a challenge to verify you have the private key, so you lose access. Just like if they lose your password hash. It's an identical scenario.