[farktronix]

It's curious that he didn't sign his new key with his old key. Does anyone have a good explanation for why he wouldn't want to do that?

[stcredzero]

If someone can crack his key old as of 2020, then they can start distributing a fake Bruce Scheneier 4096 bit key at that time. He might think it's better for him as something of a security celebrity to just publish a new key.

[emillon]

If the old key is revoked, and is the only trust path to the new one, it's a worthless key.