> installing a password manager providing passkeys would prompt to change the setting to use the password manager instead
iOS supports this today. If a password manager app describes that it implements passkey management, iOS asks what you want to be the default and the UI changes a bit to allow easier choices between iCloud and your password manager app.
It sounds like macOS is the place where Apple is lagging the most on API hooks that applications can use to trigger the UX.
It's also possible that Apple is just prioritizing that macOS users are mostly bought into the iCloud Keychain and their cloud infrastructure whereas iOS does have a large known mixture of iOS/Windows users that may bring their own keychains/password managers.
iOS supports this today. If a password manager app describes that it implements passkey management, iOS asks what you want to be the default and the UI changes a bit to allow easier choices between iCloud and your password manager app.
It sounds like macOS is the place where Apple is lagging the most on API hooks that applications can use to trigger the UX.
It's also possible that Apple is just prioritizing that macOS users are mostly bought into the iCloud Keychain and their cloud infrastructure whereas iOS does have a large known mixture of iOS/Windows users that may bring their own keychains/password managers.