This video exposes the untold history of TV spinoffs

Whatever happened to predictability? It used to be that sitcoms were a hotbed of spinoffs, either by sending away popular characters (Frasier, Family Matters) or bringing in backdoor pilots by introducing new characters onto a popular show (Happy Days, Mork & Mindy). But that practice has since been in decline, at least outside of the multigestational world of reality TV brands are constantly reworked into new versions of the same trope. So what happened to the spinoff? How did it begin and what’s become of it?