Except that this is not true. There is a FIDO specification for both a format and secure protocol for exchanging passwords and passkey information between password managers, with support on all Apple platforms, and implemented by 1Password, Bitwarden, Dashlane, and more:

https://rmondello.com/2026/09/07/switching-password-managers...

https://fidoalliance.org/download-credential-exchange-specif...