After John Bonham's death, the band quit. Right on the verge of the '80s resurgence of heavy metal, and the MTV era. What if, instead of breaking up, they just got Cozy (like it was rumoured), and carried on bringing the Zep to the 1980s and, considering it's Cozy we're talking about, probably being heavier than ever?
I think as big as they were in the '70s, the sky was the limit. Forget about Whitesnake, forget about Bon Jovi, Mötley Crue and what have you. They'd have ruled over everyone.
Or maybe not?