That depends what radio stations you were listening to. The long-gone KMET in L.A. was rock and roll to the core. KLOS and KROQ (in the same area) were also damn good.
I would also take every pre-Wish You Were Here Pink Floyd album over the 1975-2000 albums.
I'd include Animals ('77) in that pre-'75 bunch. ......and perhaps even The Wall ('80).
Even late 70s rock is not so much rock and roll.
The Stones' Some Girls sure was, as was Aerosmith's Rocks ('76), Skynyrd's Street Survivors ('77), Zeppelin's Presence ('77), Neil Young's Rust Never Sleeps ('78), Petty's You're Gonna Get it ('78), Ian Hunter's You're Never Alone with a Schizophrenic ('79), UFO's Strangers in the Night ('78), Bob Seger's Night Moves ('76), George Thorogood's early stuff. ......there was quite a bit out there if one knew where to look.
Yeah, there was a helluva a lot of total junk in the 70s as well (as you pointed out). But each decade has had more than its fair share of the unlistenable. ......the 60s included.
Prepare to be shocked. I have no use for Bob Segar or Bruce Springsteen, two icons of the 1970s who I would both put far behind the Beatles for consistency of albums.
Lester Bangs nailed Segar's music in an article that was reprinted in his posthumous book.