Historians like to paint decades with broad strokes. They like to sum it up in a few words. They wrote about the sixties to be "turbulent" and associated it with civil rights, Vietnam, protest, counter-culture and the love generation. For awhile they tried to sum up the seventies as the "me decade" but this simplistic synopsis didn't stick, even though it accurately pointed to the narcissism of disco and the arrogance of hard rock. But the seventies took many unpredictable turns. On one hand, it seemed to be a mellow decade with the rise of adult rock stations and artists like The Eagles and Fleetwood Mac. On the other hand it is remembered as a fairly wild decade with fast disco music and energetic rock bands like Aerosmith and Van Halen.
But to sum up the entire senventies as self-indulgent would be ignorant when you consider there were plenty of examples of songs that called for social unity as in "Listen To The Music" by The Doobie Brothers, "Joy To The World," by Three Dog Night and "Love Train" by The O'Jays. A lot of the pop music of the first half of the decade showcased words and melody while the latter half highlighted rhythm, arranging and performance. It actually shaped up to be a montage of all previous decades combined with more advanced and elaborate recording production. A big difference from previous decades was an angrier, more aggressive rock that emerged in two strands: metal and punk.