Maybe John Bonham doesn't
quite drink himself to death in 1980, thus Led Zeppelin stays together and goes in new and unexpected directions in the 80s?
I know: you're thinking that Zeppelin is the heavy metal that alternative music was alternative
to. And that's.. sort of true, on a macro level. But, as Robert Plant himself noted, a third of Zeppelin's stuff was acoustic. And Robert Plant is a
weird dude with some very diverse interests -- most musical geniuses are. After Zeppelin dissolved, Plant formed The Honeydrippers (with Jimmy Page!) and cranked out "Sea of Love," which you might otherwise have expected on, say,
Tom Jones's Greatest Hits. His
Now and Zen album is really unlike anything else released in the '80s (or ever, really). And after all that, Plant assembled a
folk rock cover band (
Priory of Brion), and if the phrase "Robert Plant-led folk rock cover band" isn't seven of the strangest words ever juxtaposed together, I don't know what is.
So I don't know exactly
what Zeppelin would have done in the 1980s had Bonham lived -- but I think it's plausible that it would have been "alternative" to
pretty much every song ever written before or since! Plus, there was never any real tension between Plant/Page/Jones/Bonham, so it's also plausible that Zeppelin would have stayed together cranking out music for another three decades.