The real early 70s were cool but by '73 and '74, things started to suck decidedly. But the Liberal Golden Age ended in Novemeber of '79 and the early 80s rocked!!!
I said "decade". The music of the decade of the 70's was better than the 80's or 90's IMHO. Take a look at the "charts" and they will prove me right. I think RAP led the charts from 85 to today.