Was 1983-84 the official end of the '70s culturally?

[TMC]

It was when several shows that were big in the 1970s ended their respective runs:

• Happy Days
  
  One Day at a Time
  
  Three's Company

Archie Bunker's Place (which can be considered a reformatted All in the Family), Laverne & Shirley, Little House on the Prairie, M*A*S*H, and Taxi ended their runs a year prior and Alice and The Jeffersons would end their runs a year later.

1984 was the year that The Cosby Show, which many credit for saving the sitcom format premiered. It was also the year that Miami Vice, which arguably the defined the general aesthetic of the '80s debuted.