Historical eras are all rather make believe and artificial, and vary depending on which things you are looking at to set an era for. The era of politics would be different from an era of music, and based on different opinions. On the whole, I agree that the 70s are not allowed enough to be its own era. Its generally treated as a Long 60s, a Long Hangover from the 1960s, and then proto-Reaganism for the 1980s. Honestly, the 1970s can be easily interpreted as independent from the 1960s let alone the 1980s. I would go with the election of Richard Nixon: the whole thing spiraling out of control, with this hardliner saying he'll spank everything back into proper behavior, with the hangover of the 1960s, the disillusion of the assassinations of R. Kennedy and King killing many dreams and hopes of things being set right, back to a proper course, where the system could be repaired, dying with them, the increasing economic problems of the long-Vietnam and post-Vietnam economy, and the eventual cementing of disillusion when Nixon turns out to be corrupt and exposes the whole apparatus with him, the washout of Ford, the failure of the hope invested in Carter and clean, honest government being the way forward. All ended with the election of Reagan, and that early 1980s being the morning after the drinking; the headache to get over the pell-mell, which is not pleasant but feels necessary. And you could even mark the 1970s as beginning in 1968 rather than '69, with the assassinations and the election of Nixon.