Time to take down a god as if I was Kratos:
I hate Led Zeppelin. Can't stand hearing the same few songs played for the billionth time, can't stand hearing the same weak argument again as to why they are "measurably better than everything else," can't stand Rolling Stones' old and impotent writers yet again insisting they belong at #1 on their all time lists. Regardless of merit, they don't earn this absurd endless veneration by people who need to get out more.
So in the late 60s and 70s, after the old school rock n roll era began its decline, rock music went in 2 different directions. One was so-called progressive rock (or "prog rock" now). Prog is a legit idea screwed up by an inane premise: that rock music will never be a true art unless it is "progressed" by combining with the "higher" art of European classical music. (Whether they meant it or not, this reeked of chauvinism, hence the new "prog" name to distanced it from this idea.) So a bunch of bands started throwing their noses in the air like they just don't care and turned a once danceable music into something you sit down for. Then Lep Zep came along and started using power chords in prog, which turned it into heavy metal.
So you'd think this was fine with everyone, right? Not at all. This actually caused the biggest and most important schism in the rock world. Sure plenty of metal bands followed from Zep's influence. But even as prog got started, they were faced with opposition. Iggy Pop and The Stooges, MC5, The New York Dolls, and a few others hated this new trend and purposely played against it. They tried to play a style that was old school R&R but with more of what made it not prog, which would later be dubbed proto-punk. This spun off punk rock, which itself spun off post-punk, new wave, college rock, alternative rock, and pretty much every rock subgenre that wasn't a type of metal. And the fans of those genres often were opposed to prog's offspring. (It was often said that the only band both metalheads and punks could agree on was Motörhead, who were a crossover band.) In other words, a massive amount of rock history owes little or nothing to Led Zep.
(There was also hip-hop and disco in the 70s competing with prog and metal's dominance, but to keep it simple, we'll stick to rock.)
Fast-forward to now. We've gone through so much of rock's history. So many genres, so many artists, so much music that could compete for the greatest. But despite all the greats that have existed, we still have to hear "Zep is the greatest ever" argued endlessly by pretentious people trying to show their taste is superior. We still have to put up with an aging music critic landscape still not giving the other branch of rock music credit for its artistic merit. We still have to hear "Stairway to Heaven" or "Immigrant Song" lauded as "the absolute pinnacle of rock music" 100 times a year as yet another movie, TV show, stage play, or advertisement plays them as their go-to pacifier for the audience's ears.
And don't get me wrong: it's fine if you like Zep. Whatever, you do you. But they aren't the greatest band ever, and I'll sooner listen to Wesley Willis on repeat than climb the stairway to boredom or listen to Robert Plant "YAAAAA-AAAA-AAAA-AA" again.