Sorry, but there have been just as many, if not more, death metal bands who have released 3 or more good albums as there are black metal bands. Some examples:
Incantation, if "Forsaken Mourning..." is considered as a full-length (which it practically is)
Deeds of Flesh
arguably Sepultura (three good albums, but two are more speed metal than death metal)
Celtic Frost (again, Monotheist admittedly isn't a death metal album, but then, if you include the Hellhammer stuff, they easily hit 3)
and I'm sure there are more.
What black metal bands have done this? Averse Sefira, Sacramentum, Burzum, Immortal, Darkthrone, Graveland, Ildjarn, Beherit, Bathory, Krieg, and Katharsis are the only ones that spring to mind.