>Those electronic devices that you mention don't each store the keys in a proprietary format and you can't access them without the vendor's cooperation - i.e. vendor lock in?

Passkey portability is being worked on. Here is the draft of the open standard:

https://github.com/fido-alliance/credential-exchange-feedbac...

News article: https://www.theverge.com/2024/10/15/24270875/password-manage...