I think proper WoT actually fixes this, too. No reason a system of trusted assertions couldn't also help point people to your "new npub" after losing an nsec. I attest that [wife's npub, mom's npub, best friend's npub] are the best sources of truth for "which npub vinney cavallo currently uses". If I ever lose my current npub, I tell wifey, mom, and friend to publish events that attest to my new npub being legit. Users' clients update accordingly. I'm glossing over a few ecosystem maturity and client enrichments we'd need for that to work smoothly, but at the end of the day it's just another "trust feature", IMO.