You guys conveniently ignores the fact that Apple and Google are still the gatekeepers in that scenario.
Does that service also have to trust the OS developers? Correct me if I'm wrong, but I'm under the impression that services can decide whose passkey implementations to trust.
Seems like that should be up to the user, not the service.
For example in the case of email, you generaly dont worry about google reading your email but we should definitely be concerned if gmail allows send & recieve from only few domains or providers it chooses.