Just a follow-up to my post below: if you want to see how far Happy Days fell, and how fast, you need look no further than Fonzie's first confrontation with Mork From Ork. The one thing that always interests me about these Paramount shows of the late '70s is that even though the studio had given up on one-camera filming, in favor of loud, obnoxious studio audiences, they were still resistant to the prevailing '70s method of shooting comedy shows. That is, most comedies by that point were shot and staged like little plays. Paramount was still putting in the mood music and cheesy optical effects familiar from their one-camera shows like The Brady Bunch.
And, for those of you who weren't traumatized enough by the above, there's always the Saturday morning cartoon The Mork and Mindy Laverne and Shirley Fonz Hour. Thanks again, Fred Silverman.