Def Leppard is way after AC/DC. Five years or so in origin (73 vs.77). DL are part of whole bunch of metal stuff that comes out of England at that time like Saxon, Iron Madden. Stuff that AC/DC influenced really. They - AC/DC - were pretty much a voice crying out in the wilderness of 1976 music that was this mind-numbing mixture of near-constant beginnings of disco (Play that Funky Music White Boy and Disco Lady, and You Should Be Dancin - it was hell) and lite-rock like Afternoon Delight. God it was really bleak. Captain and Tennelle AND DONNY AND MARIE and BARRY MANNALOW are ALL in the fricking charts at the same time? Oh just shoot me. Even David Bowie was doing dance stuff like Golden Years. But that first AC/DC record, well the ringing into to It's A Long Way to the Top If You Want To Rock and Roll, and TNT and High Voltage were just what a whole bunch of people, me included wanted. It's funny that Rolling Stone called it "all-time low" for the hard rock genre, because it was really part of the rebirth of Metal. AC/DC, and sort of Queen - who after the record with Stone Cold Crazy/Killer Queen went in another direction - and Thin Lizzie - that was about it in the mid-70s. (and we were about to get overrun with the Abba/Fleetwood Mac tidal wave)
There were a lot of other good ones, but AC/DC got the breaks.
There is nothing like being in the right place at the right time. Luck has a lot to do with it too. But in order to rise up you have to be able to rise up and keep on taking it to new levels, and that's harder to do than most people think it is. Every time you move out of the pub you have to keep moving the show and the music up to that level too. And they had some powerful talent. And yeah, sure it's 3 chord rock, but isn't '3 chord rock' a redundant statement in the first place?
It was crisp, had a dirty/nasty edge to it, had a heaping-helping of stupid tossed on it for fun and madcap antics, the songs were strong, and the band was tight. And though they don't really hit it big (more of a little emerging metal cult deal in the US) until after Bon Scott was dead, it was exactly that Bon Scott sound - that rawness - that gave them the initial fan base to build on. And Bon and Angus together put on hella show - and that's critical to building a fan base too. And that's what gives AC/DC the leg up on the other bands that might have been just as good, its the performance deal that puts them there, and the songwriting that keeps them there.
But the '78 performance level of If You Want Blood You've Got It is pretty damn good. I'll bite though. You have any other Aussie bands that in 1978 sound as good as AC/DC sounds on If You Want Blood You've Got It? If so, I'll listen to them too.