I was referring to passwords specifically. My statement about two passwords was not meant to be extrapolated to other pairings of credentials and shouldn't be extrapolated to other pairings of credentials. As you say, it doesn't necessarily hold up if you do.

A closer example would be one of those security token key chains which is constantly generating new passwords.

It's not having two passwords that makes it more secure, it's having the key chain and knowing password that makes it more secure.