It doesn't even take a lightning strike to get into this type of situation. September rolls around and everyone gets a new iPhone. Many forget to migrate their password manager over before sending their old phone back. Unlike the author who clearly thinks a lot about disaster scenarios and redundancy and recovery, more casual users do not. Some get lucky and are logged in to their password manager on their desktop. Some not so much and are even locked out of their AppleID credentials. Even if you remembered to migrate your password manager, you might not have remembered to bring your MFA code app.

This is the entire impetus behind Uno's productized Shamirs Secret Sharing recovery scheme: https://www.uno.app/blog/replacing-passwords-with-people. Our bet is that, like the author questions in the OP, for most people with a trusted network of friends and family, the main threat vector is not hackers and nation states trying to take over their digital lives, but rather nature, age, and accidents, etc. And that social redundancy is an acceptable risk in order to mitigate the tendency we have to want to be our own single point of failure.