Perhaps he just quickly created throwaway email accounts and forgot the passwords/recovery information.
Good point, but those weren't throwaway email accounts. I could be wrong, but he used all those email-addresses for an extended period before he disappeared.
It just bugs me. Why not use 1 email-address. Every additional email-address is an additional security risk. Especially that GMX email-address.
Why even use GMX to begin with. He goes through all that trouble to register bitcoin.org through Anonymous Speech, and then uses a GMX email-address?