Fire issue is solved with multiple backups or titanium engraving. Theft is solved with secret passphrase that is either memorized or stored in a separate location. The $5 wrench attack (aka kidnapping and torture) is unsolved but it is extremely rare in comparison to the much more common key leaks/theft scenario. And I don't believe any defense is really possible against that one, cryptographically or otherwise.
> Identity Changes, such as name changes, are relevant in the Web o Trust/GPG world where you typically require a valid ID proof (such as a passport) and physical presence before you sign someone's keys at a Key Signing Party.
It doesn't solve that problem but I don't think "real life" identity is really relevant for the purpose of contributing code. In fact, plenty of open source contributors are pseudonymous.