Are you sure iOS doesn't do attestation? Google recently turned on requiring an iOS or Google-attested Android device with a camera for some reCAPTCHA challenges(i.e. take a photo of this QR code). They waited for Apple to support it before doing so.

Is that the same thing we're talking about here? That sounds like a CAPTCHA, not Passkeys. I mean iOS isn't doing attestation in Passkeys, I'm sure there's some thing on the phone that it's doing that is a version of attestation