> But then your hardware dies

A lot of services have password reset email features. If the email account has passkey you're screwed. But restore by snail mail can be possible but slow (for paid services). More secure? Don't know but same category of problems already known due to sim swapping attacks in mobile sector. But for sure the Mail account is a high value target.

Storing passkeys in a database may be possible but complex to do it right e.g. backup verification, avoiding to leak while backup etc.